Unfortunately, the full version isn't free - but I guess the guy has to make a crust somehow :-) And I have a feeling that $5 will pay for itself in about half a day of improved productivity.
EDIT: Updated versions 27 Feb 2013
2012 Install 2013 Install Purchase License
Check it out:
"Free version provides reminders for shortcuts that contain the letter “W”. If you find it helpful and want reminders for all shortcuts, please purchase a license. "
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