Kevin has been busily working on the newest method for building a CSS model of a page accurately so that tests can be written for luminosity and contrast against styled elements on pages. Revision 144 in the Subversion repository contains an updated css.php file with a new model that gets around some weird effects of DOMNodeList when being used after XPath queries.
The next version number, 0.3 will be released once all the WW3 CSS selector tests are passed and then simpletests are also passed. We are about 70% there right now.