How do I clear my iphone before selling?

[Dingo Dave 69]

Planning on upgrading to the 3Gs today and wondered the correct process for clearing my current 3G iphone before sending it to the buyer. Can anyone help?

 

[Wolo]

I'm looking for the same information. I saw this, but I don't know if its the best way or not...

http://www.hackthatphone.com/2x/secure_erase.html

 

[horm]

or restore in itunes...