Translate

This plugin integrates the Google Ajax Language API to jQuery. You can just call e.g. $('body').translate('en') but provides callbacks for each translated element too. Or you can pass an array to $.translate to get back a translated array. Currently you can only send at most 500 characters with the raw API per request but this plugin calls them consecutively. It also reduces the number of requests by concatenating elements and doesn't send unnecessary html markup still providing access to each element as they've got translated. It provides a similar function and method for language detection too.
Here's a bookmarklet built on it: http://balazs.endresz.googlepages.com/translatebookmarklet

http://code.google.com/p/jquery-translate/