I used to own a Landcruiser and added an ipod interface. Most of them are junk. However I highly recommend the one from Dice Electronics. They all promise the world, but fail to deliver. Some only provide access through playlists which is not desirable. The Dice Unit has by far the best sound that you could find. It can be set which will allow you to access it straight through your Ipod.
It starts and stops where you left off when you turn off the vehicle and charges the ipod. I highly recommend the unit and have installed them in older generation Toyotas.