Hooray! It works!
T-mobile doesn’t have the 5.99 tzones plan anymore. They upped it to a 9.99 plan. Don’t get rid of your 5.99 plan if you still have it!!! But the tzones hack still works. To get it working on your G1, check my post about getting the MMS to work without having a data plan here.
If you want to tether your laptop to use the internet from the G1 check my post here.