This program addresses my #1 complaint about the 1-button mouse (my only complaint actually, I prefer it in most ways to three button mice, dont ask me why, I dont know) - the lack of a scroll wheel. It allows you to scroll through pages simply by placing your mouse on the top or bottom of a "scrollview" ie. webpage, text document, etc. The catch: it only works in cocoa programs. Still, pretty nifty, no clicking, just scrolling. I've been using it for about 15 minutes and I think Ive already fallen in love.
It's got settings for scrolling speeds, delays, and alternate settings as well (using modifier keys). Also, it seems the nearer you get to the edge of the screen, the faster it scrolls. Check it out:
http://www.catchysoftware.com/products/maximice/
http://www.catchysoftware.com/products/maximice/