Really well presented tutorials:
https://www.youtube.com/user/ProkoTVWeekly life drawing videos with timed poses ranging from 15 seconds to 5 minues:
https://www.youtube.com/watch?v=CO_JSrScobgUseful pic attached for the comicfags.
I don't have digital copies to share, but these are the must-have books on my shelf:
>Richard Williams - The Animator's Survival KitEven if you're not intending to make animations, there's so much stuff about body language that it will help you pick the most expressive moments for your comic panels and pin-ups.
>Jason Cheeseman-Meyer - Vanishing PointPerspective book that deals specifically with using the techniques in comics (i.e. more than just "here's how to draw a building exterior/interior", but rather "here's how to place your characters within a 3D environment").
>Stan Lee & John Buscema - How To Draw Comics The Marvel WayAn obvious classic. Each chapter is pretty short but packs a lot of useful information.
Maybe not as essential but still very good is >Dave Gibbons - Watching the Watchmen
It's the entire comic, but with the initial draft layouts, sketches, environment/character designs etc. I like it both as something to study, and also as a motivational tool - it's nice to be reminded that even the most iconic art starts out as mere blotches. That's kinda why those three books I mentioned aren't so much about drawing single body parts with photo-realistic accuracy, but rather about gestures and composition.
