iPhone / SIM card question

[The ArchAngel]

Trying to help a friend in need here, hoping I can get some clarification from the community.

I had an original 16GB iPhone, and recently upgraded to an iPhone 3GS (huge difference, btw). A friend of mine, an iPhone 3G owner, just lost his phone this past weekend. I have offered to loan him my original iPhone. What do I need to do to clear out my phone's settings and get him running on my old iPhone? Is there anything special here and is it a violation of AT&Ts terms or is this a normal practice? Does he need to go buy a new SIM card and drop that in my phone?

He only needs it for a few days until he can either locate his old phone or buy a new one, so I'd like to help him out however I can.

 

[Goodeye]

Have him buy/get (att stores it may vary some will do it for free some will charge depending on circumstances)

then wipe the phone go into settings>General> Reset> then choose your settings I assume you want all content and settings this will remove everything and put it back to a regular iphone. (or you can do a restore on iTunes)

 

[aprofetto]

I'd do a fresh restore in iTunes.

He'll probably need his own sim card.