I am planning on selling my iPhone 2g but most of my contacts are on the iPhone and not on the sim card. How do I transfer all of my contacts from my iPhone to my sim card?
I guess the contacts might get messed up when you transfer them to SIM card. I suggest you try to see if there is a way to sync your contacts with your google account or use some sort of app to backup your contact in CSV / VCF file(s).
harlemboy, on the iPhone (unless it is jailbroken) it is not possible to transfer your your contacts to your sim. in any way, transferring contacts to SIM wastes contact information such as profile pic from your contact entries. I would recommend directly exporting your iPhone 2G contacts to your PC using something like copytrans contacts.
What @raksrules said. Sync them to your Google or Enterprise or other account, and then delete everything from the iPhone. Then sync them back onto the new phone.