Looking to find a domain that was once unavailable or sell your own? If so take a look at these various domain name auction and other domain marketplaces.
Moniker – They have live auctions and provide escrow services. You can also use their domain acquisition experts in an attempt to negotiate a domain that someone may already have registered. They will attempt to acquire a domain on your behalf.
Sedo – They state to have the worlds largest domain marketplace. You do not have to buy or sell as an auction, there are fixed price options as well.
Afternic – A domain auction, buy, sell and park domains. When selling a domain through them they publish the sale through their network of partners and registrars.
NameJet – A great place to find expiring and expired domains, sold to the highest bidder.
Here are forums that also work as a domain marketplace.
DNForum – A forum about domain names that also allows you to but and sell domains.
NamePros – Domain discussions which also allow you to buy and sell domains.