there seems to be the first OTA update for the G1 today (Hoping my market-download-bugs will be fixed )
This was posted in a topic right within the t-mobile forums:
There is already an OTA update scheduled for this phone, which will be sent and installed wirelessly starting on 10/23/08, so its just thursday. this should clear up most of its issues. Hope that it does, let us know if you have any further issues. thanks for choosing t-mobile!
------Chris G. T-mobile's Tier 3 PDA and Blackberry Support
Btw: OTA - Over The Air programming
/plusminus for anddev.org