I installed the Tekonsha Prodigy and have been very happy. Here is a link to the manufacturer's website: http://www.tekonsha.com/product1.html
I tow a Jeep Cherokee on a flatbed trailer and was told by several people that Tekonsha is very good. I am happy with using it, the install was so easy and it was pretty reasonable. I think about $100. Make sure to get the easy hook up cable (about $5-10 extra) as it plugs right into the harness on the Ford van (which is near the parking brake).
I bought mine from
They are an authorized dealer with real good pricing at the time I bought it. They have an eBay store. They are in Tennensee or somewhere and I am in California but they shipped it out the day I ordered it and I got it 1 or 2 days later.
Hope this helps.