I have tried it and gave up quickly...you can tag JPG files and PSD files, but you CAN'T tag PNG files. Bridge uses metadata for "tagging" and PNG files don't accept metadata because their format just doesn't have room for it. Plus I found Bridge really slow and cumbersome. I *do* use it, but not for organizing...I use it for quickly opening up files when I'm working in other Adobe products (especially InDesign).
Libby, if you're wanting to be able to see PSD files, there is a patch out there for Explorer. It works OK...you can see a thumbnail of the PSD at least, but you can't see a full preview in filmstrip mode. But, ACDSee shows PSD files as long as you save them right.
