Nope that's the main benefit. Another thing is being able to use it even after leaving ATT.

If leaving att and also the country ;)

I did the same for my nokia 8890, unlocked so when I went to spain all I did is buy a sim card...better off price wise :thumbup:

unlocked 3G iphone + 2.1 + TMobile, does it work?

i havent seen a link that a 3g iphone can be unlocked so i can use it in Tmobile? i currently have the 1st gen iphone...

Yes it does, that's what I have using universal sim, it works great:thumbup: !
FYI Universal sim isn't a software unlock, meaning technically the Iphone is still locked according to ATT, all it does is trick the Iphone to think it's running an ATT sim. But I don't see the point of upgrading if you already have the 1st generation. You can't get 3G regardless because Tmobile 3G and ATT 3G are on different frequency... The Iphone wasn't designed for Tmobile 3G, you still gonna be on 2G or Edge which is surprisingly fast at least in the DC area.

Not only that, but T-Mobile only has a handful of cities in the US that have 3G when compared to the 3G coverage available from AT&T. That's one of the reasons why the T-Mobile G-phone isn't making a splash in the market.

LOL, I like the propaganda, I had forgotten about you Jeff ;)!