According to a recent AppleInsider report, the new iBook, which will be bearing the name Mac Book, is soon to be released, most likely later this month.

According to the report, new Mac Books will "represent the most redesigned notebooks to emerge from Apple's famed industrial design studios in several years, sources have said." Also it seems that the MacBook name is pretty much set to stone as the company has already prepared marketing materials that bear it and any attempt at changing it at this stage would be an unnecessary inconvenience at this stage of the product's development cycle.
It seems that Apple is on track with the new models and as soon as an ample supply of components is secured, the green light will be given by the management and production will commence.

According to the report, unlike the Mac mini, the new MacBooks will not be available in Core Solo configuration, each new laptop being expected to pack at least a 1.67GHz Core Duo chip.

Interestingly enough, the rumor of the MacBook appearing soon also seems to be mirrored by Think Secret.
"Apple has begun manufacturing its new MacBook and should have the laptop in consumer hands in the next 30-60 days, sources report. The MacBook-and it will indeed be called the MacBook, sources have confirmed, as Apple will be dropping the iBook moniker-is being built exclusively around a 13.3-inch widescreen display with a 1280x720 WXGA resolution, as previously reported," Ryan Katz reports.