Adam Ohern aka Cad Junkie has published a Sunglasses Modeling tutorial for Modo 501 that includes exporting to 3D print with Shapeways.
Check out the tutorial overview and his cool design, you can purchase the tutorial from Luxology for $35, the glasses are not for sale, yet..
If you do not want to part with $35 to see how the glasses were made, you can always swing over to Cad Junkie‘s site where you can check out some free, and some premium tutorials.. All of them clear, concise tutorials that are really easy to follow.
Also, take a look at the tutorials currently on the Shapeways site and let us know if there is any software you would like to see tutorials for, either step by step or video?
In case someone is interested, I made times ago a tutorial (in 3 parts) on how to design a simple die with 3DS Max and in particular, how to hollow it for Shapeways (with the small tunnel).
You can see it here: http://www.youtube.com/watch?v=M4iEJrbSOP0