I just discovered this a couple of days ago, and it is really brilliant. It's a "3D-modelling" program called Make Human.
I suppose it's not technically a modelling program, as you are not really building or modelling anything. It does exactly what the name says: makes a human. You start with a generic and genderless human mesh, then you adjust the features; masculinity/femininity, height, weight, muscles mass. Then you can go into more details, all the way down to facial features.
The part I like the most is that you can pose the human in any way you like! The joints look a bit odd, but for just getting the proportions, perspective and ang