This was written into another tip a few days back, but it's worth repeating. If you have an application with multiple open windows (such as Explorer), there's an easy way to bring all of the windows into the foreground -- simply click on the application in the dock.
If you just click on one of the application's open windows, only that one will be brought forward, possibly leaving the rest obscured behind other windows. A quick click in the dock, however, will force all the open windows to the foreground.
This is a basic functionality of the dock, but it doesn't seem to be documented anywhere that I can find.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20001217222018166