There's already a few plugins for Google's popular Sketchup 3D modelling program that permit export to formats suitable for 3D printing, but we learned that i.materialise has now released their own version.
The plugin is easily installed into Sketchup by using the instructions linked below. In the image above you can see how it appears - a simple link to a wizard that sets up your model for 3D printing at i.materialise's service. You can view examples of actual Sketchup printed models here.
We think this is a great addition to Sketchup, as it provides an extremely easy to use way to get 3D models printed. In our mind, anything that lowers the barriers to 3D printing is good. There are a great many Sketchup users and an even vaster library of models. This plugin may cause a lot more 3D printing to take place. Note: the plugin is Windows only.
This particular plugin drives printing to their service, obviously, so if you're intention is to use a different service, then you should use another plugin, such as CADSpan's. You could also consider using QuickArc's 3D viewing software, which can read Sketchup files and convert them to .STL.
Via i.materialise (Hat tip to Martijn)