I've seen talk on the interwebs regarding the use of a Data only plan in an Android Device (I'm using one on Tmobile+Nexus One at the moment), but has anyone tested whether or not it works on the AT&T network?

I have an activated 3G AT&T Microsim, and can't get it to work in my Tmo N1 nor AT&T branded HTC Aria.

I scoured Google for the correct APN settings, and nothing seems to work. When I pop the SIM into my old 2G Iphone, it works perfectly, albeit on the sluggish EDGE network only...