Flippa is an active marketplace for buying and selling websites.
NamePros is a forum that lets you buy and sell domain names and provides information on various domain related topics.
NameStation is a domain name generator which can be used to search for domain ideas, keyword suggestions, dictionary domains and more.
Namecheap is a domain registrar approved by the ICANN which provides domain registration, renewal and transfer services at a cheap price. It also provides business class web hosting at affordable prices and free SSL certificates.