I did an online Lego robotics course a couple of years ago through Carnegie Mellon University's Robotics Academy (http://www-education.rec.ri.cmu.edu/). Through the course I learned about the building and programming (using Robolab software) of Lego robots using the RCX-based Mindstorms for Schools kit.
With the introduction of the new NXT-based robotics kits this year, I have been looking into doing a similar course. The Robotics Academy is selling an NXT robotics curriculum (two-cd set) entitled, Robotics Engineering: Introduction to Mobile Robotics, Vol. 1 (http://store.robomatter.com/roenvoiintom.html) for $225.00 (US). With the purchase of the cd set you get an online teacher training course free (8 weeks).
I am considering this option so I thought I would pass along the information to anyone out there that may also be interested. The price is steep, but I learned a lot on the last course and I used the cd that I purchased the last time to teach my students.
BTW, they are still offering the RCX-based online training (8 weeks but no cd) for $55.00 (US).