T-mobile 2g suddenly shows AT&T?!!

[Alba-ny]

What the heck is going on?
I have had this 2g on t-mobile without any issue for a few weeks. The other day I updated it to 3,0 and it wourked fine.

Just a few minutes ago I went to check my email, and instead of "t-mobile" listed in the corner I saw "AT&T"
How, and why is this??? I have never had an account with ATT. (Once Verizon, but now mum took that over.) Is it some bizzare roaming thing or did they somehow automatically take me on? I am so confused. RIght now I am four hours from home, staying at my parents, and I don't have the best coverage with t-mobile, but I never noticed such a thing before.

[ohsoferrety]

It's called roaming?

[Alba-ny]

Is that really what it is then? I just never saw it happen before, and well, I guess I don't even know how roaming works to begin with.

If I go to the menu both ATT and Tmobile are listed as choices.

[ohsoferrety]

Most likely, yeah. When I'm back up at home (New Hampshire) my phone slides into ATT and Unicel, even if I go in and it shows T-Mobile as available. Most likely just has something to do with signal strength and the roaming agreements T-Mobile has with other GSM carriers.