Evan,
>Really Yahoo is were you are probably going to get most of your hits. Concentrate on getting a good listing there.
I don't agree that putting all your eggs into that basket is the best strategy. I'd recommend immediately submitting to Excite, AltaVista, Google, and about 8 or 10 other top engines, monitoring them for results on keywords and phrases, and tweaking to get better results -- and also start the process of getting a good Yahoo listing, which can take quite a long time.
I'd concentrate the efforts about 75-25 between the two, until the 10 engines are bringing in a good number of hits, then put more effort into Yahoo, if that will help at all.