The jury might be still out on the whole cell phone / brain cancer link and some might call me crazy for erring on the side of caution that won’t give me cancer, but I would prefer to play it safe.
The Pong Research cases might in fact be totally unnecessary, but if their cases really do what their pictures imply that they do, then I think that there could be a niche for the product.

Pong Research has silicone cases for the iPhone 3G, iPhone 3GS and Blackberry Curve. They diverge from typical silicone cases in two ways: they are really expensive and they contain a PCB module that Wired suggests will reduce the amount of radiation directed into the user’s head, with little to no signal loss.
The iPod models are priced at $60, while the Blackberry Curve cases (compatible with the 8300, 8310, 8320 and 8330 models) are ten bucks cheaper.

[Pong via Technabob]