I unschooled (was unschooled?) from my sophomore year of high school through college. That's, without a doubt, hugely different from doing it through elementary school I think, but I'm happy to answer any questions.
How much if any direction where you given? How where the required standardized tests dealt with? How does unschooling fit in with collage / graduate school / scholarships? Also, why did you go with unschooling over the other options?
O, and thanks for taking the time to answer a few questions.
I took a calculus course at a local community college, and my dad recommended a bunch of economics resources to me, but for programming (which was really the brunt of what I taught myself) I basically went it alone. I also spent considerable time volunteering with one of the presidential campaign's IT departments.
By the time I left high school I didn't (as far as I know) have any required testing. I took the SATs/ACTs/SAT IIs the same as any other student.
Wherever possible I applied using a college's home school form, and I wrote supplemental essays wherever possible explaining why I left my high school (especially important since I had awful grades at the time I left). I received an academic scholarship from the school I ultimately chose to attend, I assume because of my SAT/ACT scores.
I left my high school because I was extremely unhappy with it during my sophomore year. No option besides teaching myself things ever occurred to me.