What applications to use for Photo Tagging in Snow Leopard?

I've been wanting to start my personal photo library/database, and I want something to allow me to tag photos I have, add descriptions to them and search for the tags/descriptions later. I've seen something like this done on Microsoft Access on Windows (But that's a bit too hard for me, programming-wise and I don't use Windows 🙂 ). I know I can do something like this using Excel but that's not so elegant, is there a software application that does that? What do you guys suggest? 🙂
Thanks 🙂