At&t Iphone with Verizon Plan?

Okay so I have verizon but my friend is giving away her old iphone, and she has at&t. Is there anyway that the Iphone could work for me because I have verizon?

Update jailbroken iPhone 4 to iOS 6?

I'm over the jailbreak phase. Now I want to update my software but I'm afraid I'll brick my phone up. I tried to do it on my phone but it keeps saying error. Can I update on iTunes without any issues? What's the best way?

How to copy an ipod wallpaper to an iphone?

A while back, i got an ipod for my birthday, and have since then saved up and bought an iphone 4. I want to find a way to put the wallpaper for my ipod (which i no longer have saved to my computer or ipod), and make it the wallpaper on my iphone. I have no clue if there's a way to do this without jailbreaking, but if there's, it would be nice to know.

Added (1). Oh, sorry for not being very clear. Yes, it's an ipod touch. The problem is, i don't have the wallpaper saved in a picture library anymore so i can't copy it to the computer.

Weird contacts on my iPhone 4?

Ok so my dad has an IPhone 4S with AT&T and I have a 4 with Verizon and for some reason all of his contacts are on my phone and vice versa. We're both on iOS 6. I never even touch his phone why is this happening? When I try to delete on of his contacts from my phone his phone deletes it as well.