They use "early 2008" to denote the Harpertown Macs intro'd January 2008 (2.8Ghz quad and 8-core, 3.0GHz 8-core, and 3.2GHz 8-core) from the Woodcrest (2006 2.0GHz Quad, 2.66GHz quad, 3.0GHz Quad) and 2007 Clovertown (3.0GHz 8-Core 65-nm 667MHz RAM bus) machines.
There is no word from Apple, rumors, or insider sources at the moment speculating on when or what will come of future Mac Pro intros. We do know that a 6-core Xeon processor is in the works, and this will likely result in a 12-core Mac Pro machine, but we may not see it until next year.
-Ward