We already showed you guys how to unlock the T-Mobile G1. Now we're catching word that it's possible to use the G1 with no activation with no hackery or tomfoolery necessary. Simply, when you get the G1, insert an already activated T-Mobile SIM card (preferably from a very nice friend), go through the sign in process, and switch on Wi-Fi. According to the enterprising user who did this, you can do everything the G1 can do except phone-related tasks.
Be wary, we're not actually endorsing this option until we actually try it because we've already run into an issue with the T-Mobile G1 not working without a data plan. Let us know in the comments if you were able to rig this setup and have a halfway functional T-Mobile G1 with no activation!