MacMinute reported on an article at 5dias.com (Spanish) with hints from Steve Jobs about G5 laptops.
The most pertinent quote from the 5dias.com article:
Afterwards [Jobs] admitted that the decisive revolution will be the introduction in laptops of the new 64 bit chip, the G5, that the company has developed along with IBM, with an investment of 3 billion dollars. 'We are working on it and what we'd like is to have it by the end of next year', he said.
Translation by microrario and VladDracul.
A caveat: An offhand interview comment by Jobs should not necessarily be taken as a product release timeframe.