Ok, so maybe some of you might think that Babelfish's the best translator out there. I don't know about that , but I do know where my towel is ;)
So, boys and girls, here's the bookmarklet that allows to translate your current web-page using the babelfish translation engine.

javascript:location.href='http://babelfish.altavista.com/babelfish/tr?trurl='+encodeURIComponent(location.href)+'&lp=%s&btnTrUrl=Translate'

To make it useful, save it as a bookmark in FF (or as a new search engine in Opera) and give it a keyword/shortcut by editing the bookmark's properties in FF (or the search properties in Opera). Let's call him, say 'bf', that should do it.

Here are some examples:

bf en_fr
bf fr_en
bf en_ja

Enjoy!
G.R.