Prosumer Hd Camcorders Camcorders: Whats The Difference Between These?

Camcorders: Whats the difference between these? - prosumer hd camcorders

What is the difference between these 3 types of video cameras and what they are called and where can I get it?
1) http://www.mobilewhack.com/images/sony_cine_alta_f23_camera.jpg
2) http://www.itechnews.net/wp-content/uploads/2008/04/canon-xl-h1s-xl-h1a-prosumer-hd-camcorder.jpg
3) http://www.philoking.com/wp-content/uploads/2008/03/canon-hv20-hd-camcorder.jpg