Well lot of plugins are available to translate your page to different language. All major plugins use the Google Translate toolkit.
Google Recently announce the Google Translate Gadget to translate upto 51 different languages. Its very easy to implement on the side. Just copy the code and paste it on the site and its done to translate your page to user required language in few seconds (or minutes depending on the speed).
The Working:
Its very easy and a usefull tool. Like if you are a chinese guy then when you open an english site which has a Translator Gadget on that site in china then a translate button shows to convert to the local language i.e Chinese.
Here is a pic:
Click Here to go to that page to add the translate gadget on your site
Here is the original post from Google Blog
Hello from Russia!
Can I quote a post in your blog with the link to you?
Be sure to give us a link back as Copyright