Plone 3.0 is released today. Built-in versioning, slick ajax interface, and more. Pleiades will be upgrading from 2.5 in October after I get back from FOSS4G and an NEH meeting. I've already been testing our code against the Plone trunk since the start of this year and things are working pretty well. Remember, Kai has already brought PrimaGIS up to speed with the new version Plone.