Although I do not have any children that are high school age I have already begun doing research on how to keep a homeschool transcript.  It turns out that it isn’t as complicated as I had originally thought.  You simply write the subjects in as in the following examples, keep their grades and grade point average, and mark how many credits/units of attendance per class.  The following links are some excellent examples that I have run across on the web.  The first one, in my opinion, is the best one.