Dave Gwinn is still very active in teaching and explaining radar. You might try his site...davegwinn.com. His basic course is available for a very reasonable price, comes with a booklet and CD, I think.
You could also try:
Radar Tilt Management
If you really want to dive into the theory, the Archie Trammell course is still available out there. Buy lots of red bull in advance, though, because it's not physically possible to stay awake during the entire presentation without it. It's also pricey, so if you can find someone who's got it, so much the better.