I think the point I was trying to make as well as validate is that you don't have to change your physical phone when switching from AT&T GSM to T-Mobile. T-Mobile or some other agency should be able to unlock it, right?

I may make this change someday, and I like my phone. My only problem with AT&T is poor coverage in the Los Angeles metro area. But I don't think T-Mobile is any better. I'd love to hear more about how your switch goes, Goat!