I've read a bunch of posts on preparing an Iphone 3g for sale, but still don't have a clear understanding of what to do. I think my situation is a little different do to the mods. Could someone let me know the best way to go about preparing an Iphone 3G for sale with the follow setup.

iOS 4.0.2
Jailbroken
Locked (ATT)

Not sure if any of the following makes a difference.

Installed a language script to remove all languages except english and Japanese.

Removed some of the launch deamons.

I was thinking of just doing a restore to an older firmware and unlock for better resale, but I want to make sure all the infomation is removed and the SIM card is cleared.

Ultimately I would just like to get the phone back to factory settings and then work from there.

Thanks

My personal suggestion would be to restore to 3.1.3, jailbreak with redsn0w set up phone as new then unlock with redsn0w.

That would remove all personal info, also leave it in a state that is unlock safe and stable. 4.0.x doesn't perform well on a 3G and there is no safe way to go to 4.1 without losing ability to unlock right now.