Personally, I have already installed four different Android 1.5 builds onto my G1. None of them have been official releases for my exact phone so there have been a few glitches along the way. But the advantaged of the Android 1.5 update have far outweighed the downsides. If you’ve been waiting for an on-screen keyboard, stereo bluetooth, and video recording/sharing, you’re in for a treat.
T-Mobile’s Android 1.5 update will most likely take 2-3 days to roll out to all G1 users.
Source TmoNews