As previously mentioned, Apple introduced the G5 Xserves today (shipping in February).
Of interest, according to the Xserve Technical Overview PDF found on Apple's Xserve product page, the new systems utilize "single or dual 2GHz PowerPC G5 processors using 90-nanometer process technology".
Up until this point, the PowerMac G5s have used 130nm PowerPC 970s. The new 90nm 970 PowerPC chips have reportedly been in production and more information should become available in February when IBM presents the 90nm PowerPCs at the 2004 ISSCC. These new chips should offer faster speeds and lower heat production, and are widely expected to power the next revision of PowerMacs.
While no PowerMac updates were announced today, readers are reminded that Apple has recently broken its pattern of releasing only at expos. Last year's January PowerMac revision came 2-3 weeks after MWSF. Indeed, PowerMacs are promised to reach 3GHz by late summer of 2004, which would place an interim update within the next couple of months.