I have been afterschooling my ds7 since he was 4 (although, I've been calling it part-time homeschooling, hence my user name). He goes to a small private school and I work with him after school, on the weekends, and during the summer to make sure he understands and retains what he is learning in school. He has a mild case of Auditory Processing Disorder so he needs a little more time to process the information he sees and hears. Afterschooling has helped him maintain straight A's and also allows us to work on subjects he doesn't get in school, such as classic literature, Latin, Spanish, etc. So far, this has worked wonderfully for us! I started using the OPG with dd4 last week and we are now getting settled into our homeschooling routine as well.
I've been reading the WTM boards for about 2 years now and I have learned so much -- it is a wonderful resource!