The dock is a much better way to go - it is a fixed output line out signal. Meaning that you need a volume control between the iPod and the amp - a small passive will do the trick.
There are a number of them on the market. Some key differences are:
1) Some are designed to also be simultaneously used as chargers, some are not.
2) Most are designed so that a mini jack then fits into the dock plug, a few are designed so that they can wired up directly to RCAs
Worth looking into the iMod from RedWine Audio. Vinnie does some tricks to pick off the audio out right after the DAC. Its a very sweet sounding rig.
There are a number of them on the market. Some key differences are:
1) Some are designed to also be simultaneously used as chargers, some are not.
2) Most are designed so that a mini jack then fits into the dock plug, a few are designed so that they can wired up directly to RCAs
Worth looking into the iMod from RedWine Audio. Vinnie does some tricks to pick off the audio out right after the DAC. Its a very sweet sounding rig.