I recently noticed that when doing front squats (and back squats) my knees tend to buckle in as I start my ascent. I accosted the nearest brute at my local gymnasium to record these videos of said buckling. Help!
Bring your feet in about 2 on each side - they're too wide. As you stand, push your feet out against the floor. You can also try doing some basic glute strength/activation exercises before and during your squats.