i will be selling an I4, but before I do, how do I wipe the phone and get it back to factory settings? Do i need to use itunes, or can I do it right from phone??
Go into settings, go to "general" then scroll down to the bottom and select "reset", you'll want to select the option that says "Erase all content and settings" and you'll be back to default. Don't forget to remove your SIM card and you're good to go.
After, once you're done the restore to factory power off the phone pop the tray out and remove your SIM. You can tell the person you're selling to bring their own microSIM to test the phone it makes for less hassle later.
I've found that doing it on the phone versus from your computer is much faster and sets it up perfectly to sell. I've always done it with the sim in, so i would suggest that also.
If you are buying a new iPhone don't forget to plug it into iTunes one last time before you wipe it to get a up-to-date backup that you can use to restore