Re: Back squat form check, please?
I'm not sure whether you're trying to do a low bar back squat (Rippetoe style) or an Olympic high bar squat... Kinda looks like some kind of hybrid.
Anyway, my first impressions based on what I can see (next time a 3/4 view would be better so we can see more of what's going on):
If you're trying to do a low bar squat: Your knees are going forward throughout the whole movement and go way too far forward. They also seem very "wobbly" for lack of a better word. Have you been experiencing any knee pain? Only let the knee come a tiny bit forward for the first third of the movement and then they stay there for the rest.
If you're trying to do a high bar Olympic squat: Your torso needs to stay more erect.
In any case, you're not reaching proper depth. My guess is that you're not getting much hamstring involvement out of these either, am I correct? (Where do you feel sore after heavy squats?)
The quickest way, in my opinion, though would be to just read Starting Strength to learn how to squat.