According to Appleinsider, Apple is warning resellers of an upcoming "dry spell":
The company went on to warn dealers that all CPU inventory (with the exception of Power Macs) is expected to be "sold-out" by March 27th and a product dry spell would occur for approximately the first three weeks in April.
In a subsequent report, Appleinsider claims the new PowerMac revisions may not ship in quantity until before May.
Also expected are price drops on Apple LCDs next week to help clear the channel.
Despite these reports, we've heard ongoing evidence that Apple is in final preparations for new product releases. Date of official release remains unknown.