heya beezm:
I would like to point out that there is no such thing as Special "Dual Channel DDR", there are however matched pairs that are garunteed by the manufacture to work well together in dual channel mode. These matched modules normally cost more, However you can occasionally find a matched pair at the same price as it would cost to buy two individule modules seperately.
Just buy two identical modules in whatever brand, I suggest 2x512MB of pc3200 Crucial, and they will work fine in dual channel mode.
XeeN