The Greater Louisville Association of Realtors runs this page. It's a work in progress and is designed to assist agents. Again, you can search by state, city, ZIP code or MLS number. The site also has plenty of consumer information. It takes a bit of clicking to work through the search options, but they move along fairly fast.
Listings are limited, however.
It does have a pretty good list of agents and their Web sites, but many of the agents' photos are warped, which doesn't tend to inspire confidence. The search technique here is a bit of an annoyance because you can't just do a quick look for all the properties in a city. You have to fiddle around with prices and such. But the site does appear to have a fair number of listings. The virtual tour really helps because you get the preview before you actually see it.