You may be able to pick up one of the Canon Rebel series for that price as well. XT, XTi, or possibly the XSi.
Can't go wrong with either Nikon or Canon. Seems like alot of pro sports photograher prefers Canon over Nikon. I personally have Canon XSi myself and my wife uses the Canon 40D...she has used it to do a few weddings and has been great. Remember when buying and DSLR is that you are buying into the lenses, bodies are upgraded pretty much every 16months i do believe. So the investment is in the lense.
One thing I like about Nikon is that the Image Stabilizer is on the camera, so it makes the lense a little cheaper. Where as Canon lenses that have Image Stabilizer tends to add a few more $$ to the price.
Either way, he won't regret going DSLR no matter which brand he ends up with.
Good luck on search. It's too bad i sold my XTi not long ago, would have been perfect for him.
-D