Second-hand Canon D30/60 or Fuji S1 might be found for cheap if he wants something to learn on. You can get the D60 for under 1k, and the D30/S1 can be found for less than $800.
For a new one, I'd recommend he take a CF card and head to a store that has the 10D, D100 and S2 in stock and try them out. I've used all 3 and each have features that I like over the others.