iSculpt.org

One thing that it took me a very long time to really understand deep down, though I had heard it from many other sculptors, is that you MUST observe as you sculpt. Working too much from memory to soon in your development as a sculptor will ingrain some very bad habits very deeply and those will be hard to break later.

Working from a live model is the best way to wrap your head around the shape of the body, but for most of us it's just not practical to have a model most of the time. Because of this, photo references become essential.

Here are a few online resources (I'll post some dead-treeware references (aka books) in a later post) that you might want to check out. Right now, I'm going to minimize commentary on these resources and just provide links, but I do hope to do full reviews of many of these services at some point. All of the links below are likely to contain nudity, so do not click if that sort of thing bothers you.

Free
Character Designs Photosets is a resource website for artists. Among the resources provided are several photosets of people in different poses and in different outfits.

Spectrologue is primarily a stock photo resource but at this link you'll find four photosets of female models taken in many different poses and from many different angles.

Not So Free
3d.sk is primarily focused on providing images for digital sculptors and for use in texturing digital models. Despite that, there is a very wide variety of models, both male and feamale, of all different ages ages (adults only) and races, mostly nude, but some with clothes and props. Be forewarned that some of the photosets have fairly graphic nudity, including very close-up shots of genitals. 3d.sk has a couple of companion sites that might be of interest, as well: female-anatomy-for-artist.com and human-anatomy-for-artist.com which have content more targeted at traditional media artists.

posespace.com is a site run by the publishers of the "Live Model" series of books. Instead of a subscription service, they offer individual poses for sale. It's hard to compare the price to 3d.sk's subscription model, but at $5 per pose, you could drop a pretty penny to get the entire library.

Virtual Pose has been around for a while in book form, but they also sell individual poses on their webs site. At 9.95, these individual poses are rather on the expensive side.

Yes, there are many, may more, but these should get you started and were the first ones that came to mind. I'm a bit of a reference junkie, so I'll be posting more links to reference images as time goes by.