T-zones will work
The 5.99 plan will not work on the iphone you can't adjust the proxy settings on the iphone
I had installed the iPhone software unlock using the Unlock.app process. After going to Settings>General>Network>EDGE I changed APN to wap.voicestream.com, and deleted the entries in Username & Password, leaving them blank. I disabled my WiFi network to test. Went to Safari & I was able to surf no problem using T-zones/Edge. I also could check mail, use Maps etc. No Problems.
Now mind you, I had already jointed AT&T and activated my phone before all this. Then when I wanted to dump AT&T after a month & go back to T-mobile, I reinitialized my phone & started the Unlock.app process. I had no problems. Worked like a charm.
Now, my partner just bought an iPhone because I was able to unlock mine. His is not able to use Edge yet, even though he too has T-zones. Only difference is ... he never unlocked his phone with AT&T.
Now a few days after unlocking my phone with Unlock.app, my TurboSIM came in. Again, I reset my phone and started with the TurboSIM unlock. That to worked without a hitch. I am able to use my T-zones/Edge no problem.
So draw from this what you like. New phone NOT activated and used on the AT&T edge network ... can't use Edge with T-mobile & T-zones. My iPhone activated with AT&T and used on Edge, then initialized & unlocked with two different methods, can use T-zones. Hmmm ... go figure!
Okay now ....discuss.