CompuPic by Photodex is good software. It's an image management application. I use it to keep track of all the photos I take. The features I use are quick viewing of hundreds of thumbnails, the nice full screen viewer and the simple database abilities. It also has some light digital image manipulation and some fancy slideshow options I'll never use.
There are a variety of these programs for the PC - ThumbsPlus and ACDSee are popular. I like CompuPic because it was reasonably priced ($40) and because it worked best. The app is very fast: they seem to have optimized a lot of image manipulation algorithms and take advantage of hardware acceleration.