Services_W3C_CSSValidator provides an Object Oriented Interface to the W3C CSS Validator service (http://jigsaw.w3.org/css-validator/). With this package you can connect to a running instance of the validator and retrieve the validation results (true|false) as well as the errors and warnings for a style sheet.
On September 2007, I've wrote the first draft of proposal which was accepted officially by the PEAR community on October 22nd 2007.
Operating System independent.
See Download tab to know minimum and latest versions of each resource (mandatory, optional).