MacRumors.com

MacNN joins the fray and provides their own confirmation that PowerBooks and iBooks will receive updates next week.

According to the site, "Apple will introduce revised 12-inch PowerBooks (two models), two revised 15-inch PowerBooks, one new model of the 12" iBook, two new models of the 14" iBook, and a single high-end 17" PowerBook configuration".

Limited availability is expected next week.

Update: ThinkSecret also provides confirmation of a Monday release of iBooks and PowerBooks.