Top free Alternatives to iPhoto for Windows
Apple's software for viewing and managing your photos
UPDATE: Apple has discontinued support for iPhoto. You can download its replacement, Photos for Mac, by upgrading to OS X Yosemite for free. If you're already running Yosemite, you can download Photos for Mac by checking for updates in the Mac App Store.
iPhoto is Apple's flagship application for managing and viewing photos on your Mac. As a competitor to Picasa it packs a powerful punch as a slick OS X image management app that's fully integrated into iCloud, Maps and more.