Mini SIM-Micro SIM issues in upgrading...

I preorded the iPhone 4 yesterday and got a confirmation email saying that once the phone is shipped they will send me "additional information, including your phone number." I realize that the SIM cards are different but am I going to have to "change" phone numbers? Will there be a way to transfer my phone number to the new phone? I'm getting the phone shipped to me and I realize all of these issues would be dealt with if I just picked the phone up from the store.

I really don't want to do the cutting of the Mini SIM mod I've seen around the interwebs.

 

But the SIM cards are different...

 

I'm very skeptical that this is how it will work. No where on the Apple website, that I could find, says anything.

So then my old SIM would be rendered dead, remotely by AT&T after iTunes does it's thing with my new phone? Transferring my number through iTunes?

I just don't see how this is possible, through iTunes, by any avenues that I know of.

 

Thanks for explaining it more, that's what I was looking for. I'm guessing that'll crash or have some sort of problems if they couldn't even handle the simple task of pre-ordering.