Search for photos imported to your Mac OS X version from external sources. Sort the images by name, size, date, etc. Access a quick preview mode to browse the content of your gallery. Apply basic editing tools to reverse, resize, adjust the colors of images.
iPhoto is a great tool to edit and view your photos with. This program is a great way to organize your pictures and display them in a slideshow. There are many additional features available for you. Each picture can be transformed using pre-set effects and its brightness can be corrected.
The program is very Apple-generic, I must say. It looks like any other program developed by Apple. It is a photo-manager-editor - what a big deal! I mean, it does neatly organize all of your files in albums (or lists), you choose, and you can share those albums on the web... I guess it is quite unique. Most photo managers don't have the ability to upload pictures to your Facebook page, but iPhoto can do it for you. You can even tag people in your albums within the program, which I think is the best integration of a program with a network ever.
The slideshow is pretty amazing as well. There are different styles of how to display an album or an image collection.
One cool feature that I know exists, but I haven't tried it, is an ability to create a whole booklet made out of your memories (pictures). A video on Apple's website does show the end result and if you are reading this and are interested in this program, I do encourage you to check out that video made by Apple - I am pretty much sure, you will want to have iPhoto!
It will cost you 50 dollars as you have to buy iLife in order to get it. On the other hand, this includes a DVD player, a music creation tool, and an editor for the movies on your Mac, which is not bad at all.