Code School releases free in-browser jQuery course
jqueryair.com
jqueryair.com
I will say though, that after basically paying to beta test it, it does pinch a bit to see that it's free now. Oh well. I really hope these guys succeed, because they are doing great stuff.
-Gregg
Regardless this is a ridiculously polished product with awesome interactive quizes and great videos. Worth every penny, more so now that it's free :).