Not that I know of, but I do something that I find very helpful in cutting down the size of my dock. For one thing, I only keep applications that I use almost constantly on my Dock. Then, I drag and drop my Applications folder onto the right side of the Dock (near the Trash). This way, when I click on it (in Leopard), it shows a menu with the rest of my Applications. If you're using something older like Tiger, you can still do the same thing, just right-click on it or click and hold to bring the menu up.