Here is the link to Trulia's site submit page. http://www.trulia.com/submit_listings/
If you have your listings on a website, you can submit a link to that website in the box that says "Easiest" and Trulia will try to post your listings for you based on what it finds on your site.
If you DON'T have a website, you can create individual sites for each of your listings for FREE on http://www.postlets.com. Once you have created your sites on Postlets, you will see your listings on Trulia the following day.
I hope this helps!