You can do the research there but you have to have an agent that is able to bid/offer on those homes. (75% of agents are)
Im an investor, and i watch those websites each week for new opportunity. Most have a "first look" that last a week or 2 that is open to only owner occupants. Homesteps and homepath are the freddie and fannie homes and hubzu is a third party that buys distressed assets from smaller banks and then they "auction" them.