13inch iBooks along with Powerbooks
Kodawarisan reports that iBook stock is low at resellers. But they also report that alongside upcoming Powerbooks, will be 13" 800Mhz iBooks.
Apple had previously hinted that the iBook would likely remain with the G3 processor through the next upgrade. Sporadic rumors (YourDailyMac.com) hint at 1GHz Powerbooks alongside the 800mhz iBooks... but these rumors are of uncertain reliability.