I came across this site and was amazed at the variety of classes taught online here. It appears that each class is 3-5 lessons and the total per class runs $27-$45. http://www.quiltuniversity.com/classlist2.htm#Pictorial

I am looking into the machine quilting class very closely, as well as a couple of others.
Symmetry Play: A Design Game is being offered and was shown on an epsisode of Simply Quilts,(http://www.hgtv.com/hgtv/cr_quilting_instructions/article/0,1789,HGTV_3302_3378737,00.html ) Paper and Foundation Piecing is also a 4 lesson class here, fabric dyeing and painting as well as landscape quilting.
Just thought I would pass this on, scroll down through the page to see what is being offered now and at the bottom is a free class you can try out!

I am doing the Flower Power course there now . Its a 5 week class and I'm into week #4. I love it!! I have done a few courses with Quilt University and recommend it to anyone!