If you put a post on Uship.com, you can get multiple quotes back from shippers. It works quite well.
I've used uhip.com several times, for both cars and bikes, they are based here in Austin.
However, I've become dissatisfied with them, seems all bids come from brokers, I prefer to deal with owner-operators. Brokers will book your shipment, then try to find a driver on the central dispatch system, this can delay pickup of your vehicle a week or two or even cancel if they cant find a truck.
It is an interesting concept though, it's a reverse auction, the bids come in high and then brokers/drivers bid lower to get the shipment.
