I can confirm that this loop hole still works and thank goodness because I just had to cut off my internet+cable at home. I called AT&T and tried to get my unlimited data added back when the story about people once having unlimited data were being offered it back by AT&T. Well, it didn't work, AT&T claims I never had unlimited data w/ a smart phone but when I initially signed up Nov 09, I got the Bold 9700... hmm... anyway...
After being rejected I went to the AT&T store, told them my iPhone 4 was lost and showed them my 2G and said I needed a SIM card. Got the sim card for free and left.
Activated via iTunes and it switched me to the 40 dollar plan (20 text, 20, data). I then cut the new sim card and put it into my iPhone 4. I tried to goto a couple websites from my phone. I reached one website and then I got the could not activate cellular data.
So, I was in class and googled for AT&T online chat, got to the online chat and told them what was going on and he had me turn my phone off while he did a network reset. After he did that and I powered my phone on he sent me a text message with a link to a test site. I went to the test site and it worked.
About an hour after going to the test site and speaking with the rep I got the text message and email about having an ineligible data plan and they were going to put me on an eligible and they upgraded me to the 30 unlimited plan and I checked my data usage and sure enough it said 7 mbs of unlimited!!!