The broker will need to join Trulia and submit your home into Trulia Listings. There is no cost for them to join Trulia. Trulia is a wonderful tool to promote your property and get their listings more exposure. It was a home seller that introduced me to Trulia and i love it. I definately recommend it to every Real Real Estate person.
Tell your real estate agent/broker to go to http://www.trulia.com and set up a profile. Tell them that it's a website you feel would be effective in marketing your property. You can also stress to them that posting your listing on Trulia can also help promote them as well. Appeal to their marketing side.