One of my favorite features in Bridge CS3 is easy to overlook...the no folders button in the Filter panel (Window > Filter Panel).
Lets say you are viewing the contents of a folder in Bridge, and that folder has five subfolders. You want to see thumbnails of all the images in each subfolder, without opening each subfolder individually. Just click the no folders button in the Filter panel, and your view of all the subfolders will be "flattened". You will see the contents of all five folders together.
Don't be alarmed, no folders will be harmed by this button. Clicking the button only affects your view of the folder contents, not the folders themselves. The contents of the folders remain in their original folders.