With an unlimited data plan, is it not possible to just use an AIM-like service to send IMs to whoever's cell phone number you want. I know you can do that with AIM, so I don't see why you cant just do that on the IPhone and not even worry about paying the extra $5 a month. Granted, it would be a small hastle, but for $120 over the life of the contract, it could be worth it. What is the feasibility of doing something like this?