I just recently discovered Picasa's free software download. The program is very easy to download and install, and best of all it is free. The program will search your computer for pictures and add them to the system. You can sort pictures by face, tags, date, and folders.
Here are my two favorite features:
1) Fast upload from software to Picasa web album, so I can share pictures online with friends, order prints of photographs, and easily access photos for use in my scrapbook pages and genealogy work
2) Ability to make collages of your pictures, like the one pictured below:
Brenden and I at Shabbona Lake in Illinois, 2009.
Although, I've only been using the system for a couple hours, I am finding it extemely useful and easy to learn and work with.