I currently have a 3GS with 3.1.3. iOS4 comes out tomorrow and I would like to check it out. I'm wanting to sell the phone on the 23rd. I know that the unlock is supposed to come out within a few days of the iOS4 release, correct? Should I keep my phone on 3.1.3 and unlock that, or do you think I could go ahead and update to iOS4 and unlock that instead? Basically... are they releasing an unlock for iOS4 or just 3.1.3?