In case you've been hiding under a rock and somehow still believe a PowerBook G5 is coming, this c|net article should finally convince you otherwise. Michael Mayer, CEO of Freescale, states that IBM chose not to finish the work on a laptop version of the G5, partially so that they could focus more of their resources on chips for game consoles. He should a pretty good idea of the goings-on at IBM too, as he was general manager of IBM Microelectronics until November 2003.
He also states that Jobs wanted to go with Intel chips many years ago, but it was the promise of the G5 that kept Apple on PowerPC. That is not a complete surprise, since Rhapsody was even released to developers on Intel, and we are all well aware of Apple's Marklar project. Furthermore Jobs has had a long and good relationship with Intel, partially because of his days at NeXT, and because of personal relationships with Intel brass. However, back then Apple was in a precarious position, and in my opinion it would have been a lot more risky then for Apple to go Intel than now. I'm sure Jobs didn't need a huge amount of convincing to stick with PowerPC, especially when it was IBM doing the convincing with the potential of their G5.
One other interesting point made in the article is that Apple has a contract with Freescale that doesn't end until 2008. I'm not sure what that means, but I would be somewhat surprised to see G4 Macs sold after 2006. That said, there will be a lot of G4 Mac repairs needed for years to come. It is possible that this contract is simply to ensure adequate repair parts are available until institutional G4 Mac AppleCare contracts expire.