Guo Juan's Internet Go School offers both video lectures and problems available to registered members. I've gone through some of the problems on the site and they were valuable. There is great material on this site. At points navigation around the website could be improved.
Currently there is a trial period of two weeks to try out the site free of charge. Membership is €19 a month or €149 a year. Guo Juan also offers private lessons to members - perhaps one of these days I'll try one.