Not sure if this has been mentioned before but for those of us running OSX on PowerBooks (at least the 1st rev Titaniums and earlier, since I know they swapped some keys on the 2nd rev Ti) there is a very helpful key command to scroll windows in IE: option plus up/down arrow which scrolls up/down one page.
This helps a lot because we don't have true page up and page down keys. The advertised key command involves the 'fn' key which is all the way on the left and the arrows which are all the way on the right. Grrrr.
Also, just in case people don't know, command plus the up/down arrow keys navigate to the top/bottom of the current page, and command plus the left/right arrow keys mimic the "back" and "forward" buttons.
[Editor's note: These keyboard shortcuts work on desktop machines as well, since they are features of IE itself.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20020426083849708