Instant Domain Search is a great new site that allows you to look up domain name availability instantly. They use a very nice AJAX interface and some really good back-end engineering so that they can show you the availability of domains as you type them. No more waiting 10 seconds for every check. Using this domain name lookup service, it's a lot easier to riff on names and find something you like.

Also, and maybe even more importantly, they claim that they keep the looked up names private. This is an important feature. Many of the big domain name services, GoDaddy comes to mind, let other people get access to the names that have been looked up. This often leads to names getting taken if you happen to not buy them at the time you look them. Using Instant Domain Search, the name is kept private so you don't have to buy any domain that you *may* be interested in just to keep someone else from snatching it out from under you.