There is an interesting Panther dock feature that enables a small blue Aqua blob that floats above all other windows, as seen in the top portion of the screenshot to the left. When you mouse into the blob, it higlights (the bottom portion of the image). When you click on it, Exposé come on in "Application Windows" mode (higlight all windows of the frontmost app while dimming others). You can move the blob around as you might expect - click and drag it to a new location.
This hack was detailed in this thread on the MacNN Forums; it was originally posted there by the user sandsl. To enable the blob, go into the Terminal and type this command:
% defaults write com.apple.dock wvous-floater -bool trueIf you ever get sick of the blob, just execute the same command, but change true to false. You then need to log out, or quit and restart the Dock, to see the changes take effect. You can easily do this by typing killall Dock in the Terminal.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20031010141631859