On his Code Diesel blog Sameer Borate has posted about a Google Translation wrapper library that can be used to interface with Google's Translation backend.

Google translation is an interesting service. Not only can you do language translation, you can also detect the language of a particular text. I recently needed to create a Wordpress plugin to translate post titles from one language to another. As the translation API is only available for Java and Javascript, I decided to create a quick one for PHP.

You'll need to register for an API key before you can follow along with the examples. Sameer includes a few small code snippets showing how to run a "self test" to be sure things are working, a sample translation of a string and how to grab errors should they happen during the process. You can grab the library from the Google Code page for the project.