OK ... This will require some adapters, but here we go.
To get audio and video OUT of the iPod, you will need:
1. FOR THE iPod touch: An Apple Composite A/V Cable (
link).
2. FOR THE 5G iPod: Either the old Apple iPod AV Cable (
link) or a generic RCA>1/8" A/V cable (
link).
To get the audio and video INTO the DVD player, you'll need:
1. A generic RCA>1/8" A/V cable (
link).
To connect to two cables, you'll need:
1. Three RCA couplers (
link) or a 3-RCA coupler (
link).
Use the couplers to connect the Yellow from the iPod to the Yellow from the DVD Player, Red to Red, and White to White. The only exception is if you use the generic cable for the 5G iPod, then you connect Yellow to Red, Red to Yellow, and White to White.
If you're handy with this sort of thing, you can cut off the ends of a few cables and create a pair of custom one-cable solutions, but it takes a steady hand and some patience.
Hope this helps. Good luck.