Micro Endeavors has a pretty good course (at least I thought it was useful when we did our migration 3 years ago). It appears that they have a self-study course available. I don't know if it is useful or not -- we had them come here to teach a class.
http://www.microendeavors.com/>where can i find advices on migrating from foxpro 2.6 DOS/WIN to visual, ca i find documents or programs on the issue?