Perez Hilton has already called it and is sticking to the line: Fidel Castro is dead. The Miami Herald is in a holding pattern, doing a story about the rumors but leaving it at that. The most comprehensive updates are at Babalu Blog, an intensely fervent and pretty brutish anti-Castro site that I would otherwise not recommend if you're devoted to nuance, but that's the kind of ire Castro generates, so, so be it. Link.
* Updates as needed. Image above from PerezHilton.com.