How to Better Erase an iPhone When Selling/Repairing

We knew that refurbished iPhones have their previous owner's data on it, but how do you protect yourself when Apple won't go through the trouble of wiping phones out before passing them on? By unsyncing everything, then loading it up with music and videos until the phone is full to overwrite the old data that was… » 5/21/08 12:30pm 5/21/08 12:30pm