It’s becoming increasingly difficult to remember how we survived before YouTube, it is becoming an invaluable resource for tutorials and tips in 3D modelling.
One gem comes from http://go-2-school.com/ who provide video training on SketchUp via either their DVD or YouTube. Embedded below is their tutorial on how to use the Photo Match feature in Google SketchUp for Compositing:
They have 70 videos so far on their YouTube channel which is well worth a look if your a SketchUp user.
If your new to Google SketchUp you can download it for free from http://www.sketchup.com/