I have a few concerns about this posting. Please do not take offense, but I hope you understand from a business point of view, how could this client not afford to renew? In this economy a solid web 2.0 Web Presence, built on CMS technology, and properly SEO/SEM/SMM'd is a major key to success. Explain to your clients about properly building their web presence. Better yet if your not familiar with SMM than please by all means learn, or soon face difficulties yourself. I teach these techniques you can e-mail me if you desire to learn. In terms of the answer to your direct question, http://www.sedo.com has always been our premier choice for selling a domain.

     Hope This Helps,

Christopher

http://www.cwtenterprises.com "Professional Digital Solutions"