I just purchased a 2002 Rav4 and want to install one of the Scion tuners that will allow me to control my ipod and also input other audio sources.

Which model Scion tuners will allow this, and what do I need to install it ?

The T1806, T1808, and T1809 Scion headunits are iPod compatible.
You will need a cable to connect to the head unit and to the iPod.
I found someone selling them on eBay under "SC12235", purchased one , and it works great.
It allows me to select and display the playlist, artist, and song from the headunit.
It also charges the iPod.
I think that he offers a AUX in cable also.