well, I have a product like that for my cat, it is a Bamboo shedding thing. It works wonders on him, (long-haired cat) And then I take a brush to him, and it makes his coat shiny too, and not too much fur! Its lovely!
The Today Show did a couple of segments where they tried using different As Shown On TV products - Shed Ender was one of them. It wasn't very impressive to say the least.
I don't think it works if you have a dog with a short, slick, coat. I tried a furminator on Zeus with no effect.
The absolute best shed-ending product I found was also the cheapest: a $2 rubber horse curry comb from the local feed store. It makes the hair just fall off Zeus in clumps.
For longer-haired dogs, an undercoat rake from Oster does just as well, if not better, than the Furminator/Shed Enders and I think they're a lot cheaper in price.
And all around good tool for both short, medium and longer-haired (haven't tried it on super-long hair like a Rough collie or Newf yet) is the Zoom Groom. It's like $5 bucks at Petsmart. The rubber curry combs are great as well, especially for hound coats!