Sometimes you come across the damndest of things..>!
This a must-see, quirky, short tutorial, absolutly brilliantly clear and concise, with (wait for it...) the voice over generated by MS Speech to Voice (or something similar)!
Note that it covers all the basics about drawing the Classes -- but it doesn't cover Relationship/Link lines between classes.

I very much like where this app is going: its simple, intuitive, and useful.
Unfortunatly it is currently (Nov 08) only for Class Diagrams, and missing a lot of features one would expect from any other package...yet I still like it for the way it feels identical to the intuitive process of working on a paper napkin :-)

I wish I had found this page a lot earlier...would have saved my heart-ache.