Measuring!

Another great video by Sam Prokopenko.
If you care about accuracy and correct proportions in your drawing, measuring is a skill you must learn!

Drawing Eyes!

This one features Adam Hughes, amazing comics cover artist...

...And here are a couple of vids by Sam Prokopenko of  Proko.com

Drawing Made Easy by E.G. Lutz

View and download the pdf here:
http://www.scribd.com/doc/132118642/E-G-Lutz-Drawing-Made-Easy

A charming book from the past that very clearly shows how to draw using simple shapes.

Drawing on the Right Side of the Brain with Betty Edwards

If you haven't seen her classic book, "Drawing on the Right Side of the Brain", get yourself a copy!