Digitmag is reporting that specs for the PCI-Express and PCI-X protocol have been released:
PCI Express is the next evolution of PCI technology, which allows internal components of a PC, such as the microprocessor, to communicate with devices (such as graphics cards) attached through expansion slots.
PCI-X is a bus technology used within computers to allow chips to exchange data at faster speeds than current PCI technology allows.
According to this older Newsfactor article, Apple is involved with 3GIO, another high speed successor to PCI... but with possible support for both technologies:
The PCI Special Interest Group (PCI-SIG), of which Apple is a member, is attempting to push the 3GIO standard while retaining support for the still-emerging PCI-X standard. The group is telling users that PCI-X is optimized for high-end applications used on servers and workstations, while 3GIO is targeted toward general-purpose applications that run on desktops and mobile devices.