MacRumors.com

The new models will not have any new features or increases in memory or hard drive size, making them simply 'speed bump' changes. The low-end model will be boosted from 700MHz to 800MHz and the mid-range and high-end models will go from 800MHz to 900MHz.

ThinkSecret provides a detailed chart of specs for the rumored iBook upgrades.

MacRumors' Buyer's Guide shows that the iBook was last updated on November 6th, 2002 -- 152 days ago as of this writing. Based on Apple's history of upgrade intervals, it also appears that the iBooks are soon due for a revision.