This tip combines the use function of scrolling through applications as if you were using the Command+Tab keys and use of Exposé. Just how you can activate Exposé then select an application from the dock to only see the windows from that app. You can also activate Exposé then hit the Tab key to scroll through windows from that app.
[crarko adds: This usage is mentioned in the comments to this hint but it's useful enough to stand on its own. And it makes it a little easier to search for.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=201011211225369