I know you’re looking for a course, but if you’d consider a book instead I can recommend ‘Color Correction for Digital Video’ by CMP Books. It’s part of the DV Expert series. Just start at the beginning and work through the examples. That’s how I learnt. I actually had to read it twice because color correction’s one of the things I had difficulty getting my head round.
It’s pretty comprehensive covering scopes, setup, monitor calibration, secondary color correction, mattes, etc., etc.
I know it’s not a course, but it’s probably a lot cheaper and you’ll likely end up learning just as much anyway (and no I don’t work for the company, nor do I have any affiliation with the authors).
The only thing with doing this is obviously you’ll need a system to practice on… If you want any advice about plug-ins for the more advanced stuff (if you’re working on Xpress Pro or Adrenaline for example), just put up a post saying so.