well, first off, let me say that i suck and i'm no expert. now to my babble

generally good "form" i presume means no rocking left and right like the guy who's climbing is. more efficient that way. that said, a certain jan ullrich would rock left and right when he was climbing l'alpe d'huez. you just do that when you're tired and struggling and giving it everything you got. rocking back-and-forth is also something that lance does when he sprints (although that's standing), and is recommended because it's natural and gives you a sense of "rhythm". by rhythm i'm just thinking about myself when i climb a hard hill; my cadence is rhythmic, my body is rhythmic, etc. like there's a drum beating in sync with my climb, and that drum is my body.