WANTED: Building / Background Tutorials (3d?)

Ok.  I'm wanting to do some learning on how to better construct backgrounds -- namely city/urban dwellings and room compositions.
Buildings are a big hurtle for me currently.   I've heard using 3d programs like sketchup and blender can be helpful - but I'm looking on tutorials on how best to use these programs.   -- Are there others you'd use?

If you've other tutorials or brushes or any other items helpful, it's all greatly appreciated