Google Sketch Up 6 is out now. I just down loaded it for my kids. They think it's play-dough for your computer, and I reckon it's about that easy and fun. A weird thing happened when I tried to to bring a Sketch up 6 file into Revit Building 9, it crashed with extreme prejudice. I had to write about it because crashing Revit is so hard, when you finally find something that will crash it consistently, it was almost fun.
To avoid crashes for now save down to Version 5 before importing into your Revit Project.