Haven't done it, but it seems that prints at the show would give you the highest dollar sales. Secondly, perhaps use something like Collages.net for online sales. Buy their marketing kit and pass out cards/get emails from the participants. When you post online, send email letting them know pictures are ready to order.

I have a friend who does short track pics in KY. He may be able to help, if you aren't a competitor, geographically. I have done mostly hockey action, at tournaments. I've done everything from local tourneys, to state championships. I have always used film, found a Wal-Mart lab for cheap 5x7's, and sold them in TAP vertical folios. You need quick turnaround in events like this. Using digital, you've already cut way down on time. The companies that I've seen do this print proof sheets of each game, and they can also be viewed on the comp. monitors set up at their sales table. Most will take orders at the event and mail finished prints in two weeks.
Your after event sales would probably be secondary, and not as large. Of course we are talking two different types of events, and different clients as well. You can send me a PM for my friends email if you want.