Matt
Congrats on choosing a Nikon. You've bought into a great system.
I'd recommend a couple of things:
1) Get yourself a spare battery
2) Get yourself another memory card (film, never can have too much handy)
3) You might find some interesting reading here:
Nikon Digital Camera and Photography Articles by Thom Hogan
4) If you really want the pictures to turn out, be sure you charge the battery before you go on the shoot. There's nothing worse than not getting the shot because the battery goes dead.
My cameras are almost always on auto since I can't out think the Nikon guys when it comes to correct exposure settings. If you're shooting your kids playing soccer or any sports for that matter, you'll get plenty of practice panning. By the time you get to the races you'll be OK.
Good luck and post up some pics. We all love pics here.