I've seen Google sketchup in action and it is fantastic! I've even used it to design the renovations in our church chancel area (but I'm by no means an expert). Well, on my long list of things I wish I had time to do is to learn more about Sketchup. Today I came across a very long list (44!) of videos on 'The Sketchup Show.' Looks very interesting!
http://go-2-school.com/podcasts They even have an iTunes feed. And in case you didn't know, Sketchup is FREE in its basic version from Google: http://sketchup.google.com/