Each day, tens of thousands of domain names expire, and many will go to auction at GoDaddy Auctions, NameJet, SnapNames, and DropCatch.com. There are a number of tools that can be helpful for finding domain names coming up for sale in expiry auction.
I use the Basic account subscription at Dropping.com (I pay $49.95/month) to provide a customized list of domain names coming up for auction each day. The list is emailed to me first thing in the morning, and I scan the 1,000 or so domain names that meet a set criteria I have. I am sure there are plenty of other tools to find domain names, but that is the one I use every day.
Do you also use tools to find expiring domain names to bid on?