I forgot to post this before, so here's a repost of my list -

I use a variety of sources --

New Masters Academy on YouTube has a set of Clothed and Nude timed models to work with.

Onairvideo has its Croquis Café series on YouTube.
Pixelovely has its lovely Figure Drawing tool. It's Line Of Action now, as mentioned above.

I also own a copy of several books, such as Pose File (It's an entire series of books that have been going since the 90s, apparently) and the Art Models books on the Kindle Store.

Occasionally when those are all too boring and academic looking, I use the tumblr page of some French Naturist, though their shots tend to veer more into the pornographic/voyeur kind of territory more than I'm comfortable with.