Welcome to Trulia Voices and thank you for your question. I'm afraid that the photo slideshow on listings cannot be replaced with a video at this time. I'll be sure to share your request with the rest of our team.
Please note however that our blogging platform allows you to display YouTube videos within your posts and you are free to blog about your listings on our site. Please access http://www.trulia.com/blog/post/
if you are interested in creating such a blog and let us know if you have any other questions or feedback.