PhotoSift is a free utility helping you to quickly organize unsorted image libraries. The basic idea is to load the program with images, then show and inspect each image and press a key on the keyboard. The image will then be moved or copied to a folder of your choice corresponding to that key, and the next images is displayed. This allows you to rapidly go through and organize your large amounts of pictures.
Download the application at http://rlvision.com/photosift