Invoking Exposé from the Dock, to view a single application's windows, is handy. But what if you want to view the windows of more than one application, without viewing them all? MacOSXHints.com reader kapeli explains how:
You probably know about Exposé's application mode. What's interesting is that, while you're in it, you can Command-click on other running applications and bring their windows into Exposé as well.
To do so, click and hold on any running application in the Dock. Then Command-click on the icon of another running application in the Dock. The windows of both applications should now be visible in Exposé. You can Command-click on more applications and bring their windows into Exposé as well. (Note that some windows that Exposé normally ignores may appear when you do this.)
Remember that you can also remove a program's windows in Exposé, by Option-Command-clicking on its dock icon. Neither of these tricks will work on windows that are minimized or hidden. Still, if you generally have a lot of windows open at once, and want to see just a few of them in Exposé, these are both handy ways to do so.