As a general rule, if a company like Google makes something hard to do, it's because they don't want you doing it! And if you DO figure out a way to do it, all they have to do is make one little change and all your stuff breaks. Most of the info they're willing to share is available via published APIs. You just have to do a little digging to find them all.

Try starting here:

http://code.google.com/intl/en/