Quite often the OEM Ipod interface is more expensive than getting a new deck. Also, they usually only supply you with an input, not a full working display that comes up with artists, playlists and whatnot. Charging is a whole other story.
That said, just getting a simple USB deck installed will get you a much better way to control the Ipod, charge it and give you better overall sound quality. When it comes time to sell the car, you can throw the old deck back in with no problem. No animals would be harmed in the installation of the deck.