Apple offers a page of tips for each application that it makes, and some for various aspects of Mac OS X.

A little known page on Apple's web site is the Tiger Tip of the Week, which gives a weekly tip about any of the applications included with Tiger for free. Most of the tips concern the Dashboard and the Finder, but there are also tips on Safari, TextEdit, System Preferences and Spotlight.

In the support section of the Apple site lies the "Hot Tips" page for each of the iLife Applications. These aren't updated often, but contain a few gems, as they are written by people who really know their stuff. Get tips for iMovie, iWeb, iDVD, GarageBand and iTunes.

Of course Apple wouldn't provide Hot Tips for iLife while neglecting iWork, so there are also tips for Pages and Keynote.