Teaching myself java programming

I recently got a T-Mobile G1 phone. This phone runs Android OS and apps are written in java. I have set up the development environment on a couple of my computers. I have been working through the tutorials and looking at source code from open source projects. While doing this I found the source code for Android-Identities and A-Blogger. I have built both of them and am currently using them. After I understand them better, I am looking at expanding the features of them.