Originally Posted by DaveStockwell
Check into Virgin Mobile. I believe they offer plans for SIM cards only. The others might but you aren't going to find them advertised that well. From the shopping I've done, over the long term (and especially if you use a lot of data) your most cost effective route will be to take the ATT upgrade.
Virgin Mobile only supports CDMA--no SIM cards. They also will only activate Virgin Mobile phones. Theoretically Sprint phones would also be able to be activated and I've seen stories on the net where people have been able to talk the customer service rep into activating a Sprint phone on Virgin but it's not company policy.
My phone is $35/mo, unlimited text and data, 300 minutes of talk time. I bought my Optimus V used for $50 with an otter box case and screen protector.