LOL, iPhone! Did the glitter get you? Read this: http://www.mobile-review.com/article...phone-en.shtml
then think again! With an iPhone you can't even do half as much as with a PDA phone - however, it's your choice!
The best options for making your phone good for selling, is: BE HONEST TO YOUR BUYERS ! Show them detailed pictures of the item and do not forget to mention if the device has any scratches or other problems! This will save you lots of stress, believe me!
Also you should reflash the device to its shipped ROM and take off Hard_SPL and all that stuff - try to get it as original as it was when you bought it! Including some apps and application won't raise more cash out of the buyers pocket and whatever you 'styled' and 'modded' on the phone reflects only your personal taste, so, a buyer might not share the same likings!
Maybe that helps?