iPhone 3G Cracks, warranty and jailbroken iPhone

[dontwalkhand]

The case on my iPhone 3G is cracked, the Apple store is replacing it tomorrow, but what do I need to do?

Should I flash my iPhone to the locked AT&T version prior to bringing it in? It is unlocked 2.2.1, and unlocked using a "3G-SIM"...with UltraSn0w coming out soon, should I just up it to 3.0, bring it into Apple, and then unlock and jb myself when I get it back? I will put my SIM into an unlocked backup first generation iPhone for the time being. I purchased AppleCare for it, and it has an Apple Warranty until Aug 2010

 

[dontwalkhand]

Also, forgot to add, it is near the dock connector area, it is bad that you can move it. I have made an appointment with Apple, should I flash the phone beforehand or are they ok with it now?