Google's Picasa

Picasa is free downloadable software from Google that helps you instantly find, edit and share all the pictures on your PC. Each time you open Picasa, it automatically locates all your pictures (even ones you forgot you had) and sorts them into visually organized albums. You can drag and drop to arrange your albums and make labels to create new groups of photos. Picasa makes sure your pictures are always organized, and advanced editing is simple with easy to use one-click fixes and powerful effects. It's easy to share your pictures, allowing you to print, email, or upload photos to Picasa Web Albums with just a click.

http://picasa.google.com/index.html