The Register Compass service shows us a list of already expired domains and expiring domains. They can be sorted by pagerank, by Alexa traffic, and many other caracteristics. Read more details on Register Compass
There are not many good web services like this one. Register Compass is one of the best because they offer dynamic list of expired domains, updated frequently. The tell you exactly that the domain name expired on (precise date), they group the recently expired domains. Even if you find a expired domain that was already bought, you mark it and the list wil update in a few seconds. With this service, our company bought a old domain mane that expired recently. The domain was active for 8 years, but the domain owner had better things to do and amabdoned it. The abandoned domains are one of the best way to start a new website, because the age is a very important caracteristic when ranking in search engines. Try it yourself: Register Compass.