I was looking for a good medium to practice my figure drawing skills online. One very good website I manage to find was called posemaniacs.com. This website provides you with a very nice flash application that shows you various poses every 30 to 90 seconds, and the durations are configurable. The models are all modeled in 3d with a turn around. This allows you to be able to draw the same pose from many different angles. On top of that, the major muscle groups are also shown clearly on all the models which makes it really handy for both beginners and even professional artists.
And here are some of the tips that I have figured out when practicing figure drawing. The shoulder and hip positions should be determined in the very beginning of the sketching process, as they will determine how the main pose is going to look like. On top of that line of action is also very important, it will not only help you make the action more expressive but also provide you with a guide on the center of gravity.:)