I'm Andrew, a community manager here in Trulia Voices, and so can speak on Trulia's behalf.
Anna and Tim are quite right in saying that only real estate professionals can list homes for sale on Trulia.com. We've built a "Find A Pro" tool to make it easy to find real estate professionals based on recommendations from other home buyers and sellers, and how active and knowledgeable they are in the Trulia community. You can find that tool here: http://bit.ly/IKgpiE
Let me know if there's anything else I can do to help, either by responding here or at my email below.
Community Manager, Trulia Voices