The seminars are listed on US SAILING's calendar on their web site.

Here's a direct link:
US SAILING Race Management Seminars

The best time to take these is in the winter. I did the Advanced RM seminar in January, taught by Tom Farquhar (the guy who literally wrote the book) at the St. Pete YC.

I know Mike Levesque just took the ARM seminar last weekend taught by Peter Reggio - he's the guy that runs the signal boat at a little event called "The America's Cup".