You can find domain names that are expiring with JustDropped and SnapNames.
This can be a good idea because if a domain is expiring, it means that someone thought it was a good idea. A lot of people come up with clever domain names or great business ideas, register the name, and then never do anything with it and let the domain name expire. Other times, businesses just fail and their domain names expire because no one cares to renew them.
Sometimes these expired domains have a long history or even existing backlinks, which is a good way to get a new web project started off on the right foot.
