Here's yet another useful keyboard tip repository: Windows keyboard shortcut of the day
And today they happened to share something I didn't know about getting Windows (XP in the tip, and Vista in a comment I just left) to help you see underlined letters for doing shortcuts.
Despite the site's name, the tips aren't generally updated daily (last one was in April), but that's ok by me. Heck, you'll want to troll the archives for past goodness. Plenty of gold in "them thar hills". :-)