Okay. Anyone with a G1 from T-Mobile who suddenly find yourself without 3G or EDGE service. This is what you need to do.
Call T-Mobile or log online to select the plan that you want again. T-Mobile dropped the ball and is not make the switch automatic.
Supposedly, after you select a plan, it may take 24-48 hours to activate.
Hope this helps. Let me know if you've still got issues. My services returned to normal after 30 minutes. But it may take up to 48 hours.