There is also a very nice Vim Quick Reference card available
here . It is GPL and the tex source is available from that URL also if you would like to modify it in order to suit your particular usage habits.
It is by no means complete, but the author chose probably the most used commands. This card was invaluable to me when I began using Vim and it is still reference once in a while.
Have fun.. Learning Vi is effort well spent in the long run.
~arker