I don't have a lot of images on my hard-drive at the moment, so I don't use either of these, but I think Photoshop Elements 4.0 has a tool to organise and catalogue images, or if you prefer free (and who doesn't ) try Google's Picasa.
I heartily reccomend Picasa. If you have a GMail account then sign up for web albums and get the Picasa Beta which features better folder integration. You don't have to use the web albums!