Now that mesh is available gridwide, this looks like an especially useful tutorial for creating and importing mesh objects for Second Life in Google Sketchup:
There's advantages with using Google Sketchup, versus other 3D building tools: It's free, for one thing, and looks much more user friendly then most other 3D modeling software platforms. (Experienced modelers, correct me if I'm wrong on this point.) My favorite part of the video happens around 4:50, where the mesh goes from Sketchup to SL:
As you can see in the demo, there's a lot of dynamic customization (size, texturing, and so on) that you can do with the mesh object once it's in SL. When mesh for Second Life was announced a couple years ago, there was a fair amount of talk that the offline building tools needed to make mesh would dilute the magic of dynamic, collaborative creation in SL, one of the world's most distinguishing features. But even if we see less prim-based, prim-by-prim building, I think we'll still see a lot of dynamic building in-world with mesh.