You can tow manual trannies in neutral.
Automatics must have the drive wheels off the ground or have the drive shaft removed, (rear wheel drive).

The latest Saturn and Cavalier are the only two autos I know of that can be towed in neutral.

Next time you're on I-75, notice all of the motorhomes coming out of the north with a car in tow. Most people choose a Suzuki Tracker, or Jeep Wrangler, because you can disengage all axles from the transmission through the transfer case.