My GoogleAPI JS Class for Mozilla can be downloaded here: GoogleAPI.js . It is licensed using a three-clause BSD license, so you are free to use as you please. If you use this as part of an application, I'd like to know about it so I can add you to this page.
Feel free to email me if you are using my GoogleAPI JS Class in any of your product, and I'll include a link to it here.
Jesse Ruderman has created the Google Relateness tool which calculates how related two words are.