@Tom Chiverton
I was actually surprised, T-Mobile did actually issue an update in the four months I've had the G1. Doesn't mean they'll also issue *this* update, but it at least leaves the possibility.
And in case anyone is wondering why the G1 and not the iPhone, it's simple economics to me: the G1 is cheaper than the iPhone. Being linux-based also has a certain geek-factor to it, even if it might ultimately mean nothing.