Downloading non-market applications from our AndroidApps directory is simple on Android. Here’s what you do:
First, head over to the main settings of your T-Mobile G1
Then go to Applications>Unknown Sources and click OK
Visit Android Apps and download your desired application (should have a .apk extension)
Run the file and install the app
Remember: you won’t be able to view the application from Market Downloads but it will be available in your “pull-up” menu and you can add the icon to your desktop by long-pressing and selecting it in “applications”.