The following instructions make it easy to post to Twitter and Jaiku from the command line. The instructions were copied from the article "Ubuntu Unleashed: Howto Twitter From the Command Line in Ubuntu!" [ubuntu-unleashed.com] and modified to post via Rorbuilder's ProjectX API.

sudo apt-get install curl

sudo gedit /usr/bin/jaitwit

Now Paste this in gEdit and simply replace "YourUsername" with your username and "YourPassword" with your twitter passwd, then replace the Jaiku variables (YourUsername, YourPassword, YourCity, YourAccessKey) and ctrl-s to save, then alt-F4 to exit!

curl http://rorbuilder.info/api/projectx.cgi?xml_project=%3Cproject%20name=%22micro_blog%22%3E%3Cmethods%3E%3Cmethod%20name=%22post2jaiku%22%3E%3Cparams%3E%3Cparam%20var=%22user%22%20val=%22YourUsername%22/%3E%3Cparam%20var=%22msg%22%20val=%22`echo $@|tr ' ' '+'`%22/%3E%3Cparam%20var=%22location%22%20val=%22YourCity%22/%3E%3Cparam%20var=%22apikey%22%20val=%22YourAccessKey%22/%3E%3C/params%3E%3C/method%3E%3Cmethod%20name=%22post2twitter%22%3E%3Cparams%3E%3Cparam%20var=%22user%22%20val=%22YourUsername%22/%3E%3Cparam%20var=%22msg%22%20val=%22`echo $@|tr ' ' '+'`%22/%3E%3Cparam%20var=%22password%22%20val=%22YourPassword%22/%3E%3C/params%3E%3C/method%3E%3C/methods%3E%3C/project%3E -o /dev/null
echo Message Sent!

Then chmod for exec privileges:

chmod +x /usr/bin/jaitwit

Then from the CLI type jaitwit followed by your message.

jaitwit "message here without the quotes"

This example uses the ProjectX API to post to Jaiku.com

<?php
  $msg = 'this is just a test message using the ProjectX API for posting to Jaiku';

  $xml_result =  simplexml_load_file('http://rorbuilder.info/api/projectx.cgi?xml_project=<project name="jaiku"><methods><method name="post"><params><param var="user" val="jrobertson"/><param var="msg" val="' . $msg . '"/><param var="location" val="London"/><param var="apikey" val="9ee6ffd165r364492"/></params></method></methods></project>');
  $method_result = $xml_result->post2jaiku;
  echo 'result' . $method_result;
?>

Reference: SimpleXML processing with PHP [ibm.com]

This XML code is the ProjectX API to post to both Twitter and Jaiku. This is a follow-up example from Post to Jaiku using ProjectX API [dzone.com]

xml_project = <<PROJECT
<project name='micro_blog'>
  <methods>
    <method name='post2jaiku'>
      <params>
        <param var='user' val='YourJaikuUserName'/>
        <param var='msg' val='YourMessage'/>
        <param var='location' val='YourCity'/>
        <param var='apikey' val='YourApiKey'/>
      </params>
    </method>
    <method name='post2twitter'>
      <params>
        <param var='user' val='YourTwitterUserName'/>
        <param var='msg' val='YourMessage'/>
        <param var='password' val='YourPassword'/>
      </params>
    </method>    
  </methods>
</project>"
PROJECT

This Ruby code uses the ProjectX API on rorbuilder.info to send a post to Jaiku.

Prerequisites:
1) You have a Jaiku account. see http://jaiku.com/
2) You know your Jaiku API key. see http://api.jaiku.com/

#!/usr/bin/ruby
# file: projectx_client.rb

require 'net/http'
require 'rexml/document'
include REXML

class ProjectXClient
  attr :doc
  def initialize(raw_url)
    url = URI.escape(raw_url)
    xml_data = Net::HTTP.get_response(URI.parse(url)).body
    @doc = Document.new(xml_data)
  end
  
end

if __FILE__ == $0

xml_project = <<PROJECT
<project name='jaiku'>
  <methods>
    <method name='post'>
      <params>
        <param var='user' val='YourJaikuUserName'/>
        <param var='msg' val='YourMessage'/>
        <param var='location' val='YourCity'/>
        <param var='apikey' val='YourApiKey'/>
      </params>
    </method>
  </methods>
</project>"
PROJECT
  
  pxc = ProjectXClient.new("http://rorbuilder.info/api/projectx.cgi?xml_project=" + xml_project)
  doc = pxc.doc
  puts doc
    
end

You can also pass the url including xml into the address bar and it will post to Jaiku successfully.
eg.
http://rorbuilder.info/api/projectx.cgi?xml_project="<project name='jaiku'><methods><method name='post'><params><param var='user' val='jrobertson'/><param var='msg' val='testing 223'/><param var='location' val='London'/><param var='apikey' val='5ugr6ttr754y214445'/></params></method></methods></project>"

Note:
Your api key is not in any way stored by the website rorbuilder.info.
Rorbuilder.info is a 3rd party developer website which is not part of Jaiku.com.

// example configuration file for jaiku.py

config = "jaiku.conf"
xmlrpcurl = "http://api.jaiku.com/xmlrpc"
feedurlstart = "http://"
feedurlend = ".jaiku.com/feed/atom"
itemdelimeter = "<entry>"
titledelimeter1 = "<title>"
titledelimeter2 = "</title>"
username = "mcandre"
personalkey = "FILL IN YOUR API KEY HERE"
location = ""

// Set and view Jaiku statuses

#!/usr/bin/env python

__author__="Andrew Pennebaker (andrew.pennebaker@gmail.com)"
__date__="28 Jun 2007"
__copyright__="Copyright 2007 Andrew Pennebaker"
__license__="GPL"
__version__="0.0.1"
__URL__="http://snippets.dzone.com/posts/show/4223"

import sys, getopt, urllib2, xmlrpclib

import configreader

STATUS_MODE="STATUS"
VIEW_MODE="VIEW"

def set_status(settings, status):
	s=xmlrpclib.ServerProxy(settings["xmlrpcurl"])
	
	calldata={"user":settings["username"], "personal_key":settings["personalkey"], "message":status, "location":settings["location"]}
	
	try:
		s.presence.send(calldata)
	except:
		raise "Could not connect."

def view_status(settings):
	item=settings["itemdelimeter"]
	t1=settings["titledelimeter1"]
	t2=settings["titledelimeter2"]

	try:
		instream=urllib2.urlopen(
			settings["feedurlstart"]+settings["username"]+settings["feedurlend"]
		)

		for line in instream:
			if item in line:
				break

		title=instream.readline()

		instream.close()

		status=title[title.index(t1)+len(t1):title.index(t2)]

		return status

	except IOError, e:
		raise "Could not connect."

def usage():
	print "Usage: %s [options]" % (sys.argv[0])
	print "\nWithout any options, uses status mode. Leftover args are concatenated to form message."
	print "\n-u|--username <username> specified in jaiku.conf"
	print "-p|--personal-key <key>"
	print "-l|--location <location>"
	print "-s|--status mode"
	print "-v|--view status"
	print "-c|--config <configfile>"
	print "-h|--help"

	sys.exit()

def main():
	global STATUS_MODE
	global VIEW_MODE

	systemArgs=sys.argv[1:]

	mode=STATUS_MODE

	settings={
		"config":"jaiku.conf",
		"xmlrpcurl":"http://api.jaiku.com/xmlrpc",
		"feedurlstart":"http://",
		"feedurlend":".jaiku.com/feed/atom",
		"itemdelimeter":"<entry>",
		"titledelimeter1":"<title>",
		"titledelimeter2":"</title>",
		"username":"mcandre",
		"personalkey":"",
		"location":""
	}

	optlist, args=[], []

	try:
		optlist, args=getopt.getopt(systemArgs, "u:p:l:svc:h", ["username=", "personal-key=", "location=", "status", "view", "config=", "help"])
	except e:
		usage()

	for option, value in optlist:
		if option=="-c" or option=="--config":
			settings["config"]=value

	try:
		configreader.load(open(settings["config"], "r"), settings)
	except IOError, e:
		pass

	for option, value in optlist:
		if option=="-h" or option=="--help":
			usage()

		elif option=="-u" or option=="--username":
			settings["username"]=value
		elif option=="-p" or option=="--personal-key":
			settings["personalkey"]=value
		elif option=="-l" or option=="--location":
			settings["location"]=value
		elif option=="-s" or option=="--status":
			mode=STATUS_MODE
		elif option=="-v" or option=="--view":
			mode=VIEW_MODE

	if mode==STATUS_MODE:
		if len(args)<1:
			usage()

		message=" ".join(args)

		set_status(settings, message)
	elif mode==VIEW_MODE:
		print view_status(settings)

if __name__=="__main__":
	try:
		main()
	except KeyboardInterrupt, e:
		pass