What do I do before selling my 3Gs?

[darthdad]

I am an Android guy, but was given a pair of 3Gs iPhones in trade for some work I did. What do I need todo to the phones prior to selling them to make sure all data is removed and no trace of previous owner is on it? Also should I remove sim before selling?

Thanks!

 

[Sonlon]

I will remove all the data on that phone before I sell it,Including format the phone. But I may keep the SIM card.

 

[Tanbam]

Don't worry about the sims. They should already be deactivated, and if the buyer wants to use it like an iPod, keeping the sim in it may help them activate after a firmware update. No reason to make life any harder for them.