When I was a t the 2008 Donnie Smith Invitational Bike Show recently, I ran into these guys from Condor. I was thoroughly impressed with their line of products that they were demonstrating.
They have fair prices, and really cool lifts, chocks, trailer stops, etc. plus the line of products was extremely user friendly, which is what I liked about them.
Here is a picture of the Pit Stop/Trailer Stop (PS-1500) I'm thinking about getting, as my wife wants me to build a smaller bike trailer.
All you have to do is roll the front tire in and it automaticly self locks the bike into place.
Secure the back, and you are ready to roll.
If you want to check out their site, here is a link.
http://www.condor-lift.com/