On a recent trip to Hawaii, I got introduced to Apple's iPhoto software on OSX. I thought it was a decent piece of software, but a bit basic for me and there were a couple of minor bugs. My trip did show me that I probably should use something to help me manage my digital photos as my collection has gone past hundreds to thousand(s), so once I got back I tried out Picasa. Picasa is a photo management software that was bought by Google and then released free. I heard good things about it including that it was a better iPhoto then iPhoto. It runs on Windows with a Linux version in beta.
My experience so far with Picasa has been good. It is as simple as iPhoto and has the same basic functionalities. When it is first installed, it asks you if you want it to search your computerfor all graphics files (pictures and movies) or limit the search to the "My Documents" folder. I wish it allowed me to enter a different location since I don't keep my photos there For some reason, PNG files aren't enabled by default, so you have to enable that yourself.
Overall, a neat program with a great price. If you take a lot of digital photos and need a quick, fast and easy program to management those photos then definitely give it a look.