I'm on the sprint hero right now. It's amazing, but I think the iphone might be better. (I'm using an iphone without service right now and like it a lot.) So if I sign up for a two year contract right now, the minimum they'll give me, when the iphone 4.0 comes out next summer what options will i have to get it without paying full retail price? Can I just pay the ETF and re-sign up? Or will I need to sell my phone and buy the new one retail?