Dr. Carol J. V. Fisher has created a thorough online Algebra 1 course complete with interactive exercises for every topic. You can also choose to have a worksheet of practice problems and answers generated. I haven't explored the site that thoroughly yet, but there's a link to a beautifully formatted pdf text for each topic and the interactive web exercises are of good quality. I love that there's an option on the trinomial factoring problems to show the graph of the associated quadratic function!There are also lots of interactive exercises for Geometry and Algebra 2.
