Valve released the Left 4 Dead Authoring Tools recently, which included some plugins for Google SketchUp. In this video, I’ll show you the basics of exporting SketchUp geometry into the .VMF format. The plugins export generic VMF data, so it works with other Source games too. Contrary to what I said in the video, valve has included the plugins with the regular SDK now.
I have a cold so my voice is a bit off in places. Send plugin feedback to sketchuptools@valvesoftware.com.