In a post aptly titled 'At Long Last!', Unsanity announced a beta of a Universal version of ShapeShifter, their UI haxie for skinning Mac OS X. As the post states, your Intel Mac can finally "get its spank on" (what on Earth are those guys at Unsanity selling??). Obviously, as their post states, this is a beta so things could very well go wrong with it. On the upside this Universal version should work just fine with any guiKit (skin) that you throw at it.
This ShapeShifter 2.4 beta version is a free upgrade for registered 2.x owners and is available from this Unsanity blog post.