Skype is looking for a little cooperation with cellular carriers, asking for permission to piggyback on their networks to provide VoIP calls. That asking is actually a petition filed with the FCC, and the petition asks the governmental commission to force the major cell providers to adapt their networks for such “outside” calls.
The same sort of operation was forced on AT&T as that company was being broken up. (That company is now plenty big, although one of its children now owns the parent; but that’s another story.)
Basically, Skype wants open standards for cell phone protocols. They want you to be able to use their technology but use someone else’s network. It’s sort of like using your phone company’s Internet connection but going with another provider. It is open source, though, in the way that Linux is and in the way that many people want Microsoft to be.
So far, Skype is on its own, although other VoIP providers might soon follow suit. The reaction from the cellular community was swift and predictable. They don’t have to share their networks, so why should they? It’s a fair enough question to ask. Skype wants that question answered in its favor.