Yesterday, I blogged about personal data being pulled off of refurbished iPhones due to the special type of NAND memory used on current iPhones. Today, I stumbled across an article written by Securosis.com which may bring a solution to this problem. In short, it involves the use of three very large playlists which will attempt to overwrite your memory with enough junk data essentially burying your relevant personal information. Read on to get the full scope. (Source: TUAW)
Note: this has not been professionally tested, so please be mindful as to what you should do with your unwanted iPhone.
Update 07/08/08: iPhone 2.0 Firmware to offer "Secure Erase" function.