Several prominent rumors over the past few months have indicated that we may see shipping PowerMac 970's at or around the WordWide Developers Conference (WWDC) on June 23, 2003.
While early rumors have indicated that 970-related announcements/demos will be conducted at WWDC... the most optimistic claims indicate near-immediate availability.
Recent information, however, suggests that PowerMac development is still ongoing, and neither finalized nor in-production at this time. This would suggest that PowerMac 970's would not ship until some time well after WWDC.
(This information does not exclude the possibility/probability that the PowerPC 970 may be demonstrated/discussed at WWDC.)