Firewire 2 or 1394b's design standard was approved in March 2002. Firewire 2 promises to bring longer device-to-device distances, faster speeds (800MBits/s at the low end), full duplex communication, lower costs and backward compatibility with the original Firewire.
Newsfactor reported in May that Firewire 2 would not likely make it into the most recent PowerMacs... and the subsequent PowerMac released did not contain this new technology.
However, compelling evidence of Apple's work on Firewire 2 came from an internal Apple PDF which outlined an Apple PowerMac design with Firewire 2 ports included. This PDF was accidently left exposed on Apple's website, and was quickly removed from their site.
Future PowerMac upgrades are not expected until after MacWorld SanFrancisco, but it appears that Firewire 2 is due, and reported to be pending the next revision based on the current whisperings.
In related news, Apple released IP over Firewire Preview Release. With theoretical max speeds up to 3.2GBits/s and 100meter distances, Firewire 2 (1394b) could prove useful in a local networking connectivity.
Further details about Firewire 2 is available at 1394ta.org's site.