How to reset/restore a locked iphone 3g?

My friend was using my iPhone before he broke the screen on it. I fixed the screen to use it again. He had a passcode on it, which he doesn't remember. THE PHONE WAS NEVER SYNCED TO MY ITUNES. How do I get the code off? It doesn't matter if all the stuff on the phone is lost. I'm just going to reset it anyways. I've done it before but I don't remember how.

1.Download the latest iTunes
2.Connect your iPhone 3g on your Computer
3. The Computer Will Read the iPhone and It will Say Restore
4.Click That
5. IPhone will update, and every data of his iPhone will be completely erase/deleted.
6.It may take 10-15 minutes, just wait
7.Done! New iPhone