Many of these other sites are for consumers to view property that fall within some level of seach parameters. The listing agent has their information at the bottom of the page. You can e-mail them directly for more info or visit their brokerage site for more detail.
I do agree with Ms. Levy in working with an agent/broker. If you are "just starting" then enjoy the lovely photos and floorplans. If you are serious and prepared to move forward, call a broker. Good luck.