printedsolid - There are plugins for sketchup that you can download to export to stl from sketchup. If you search in whatever they call the plugin warehouse, you should be able to find one pretty quickly.

However, there are a bunch of technical problems that can come up in the export due to the way you built your model that can cause problems in the processing required to turn the model into code that the printer can use. The model might look great on the screen, but might have gaps in the mesh, overlapping edges, or 'inside out walls' that will cause odd results or inability to process at all.

To deal with this, I usually point people to netfabb, which has a free version for model repair: http://www.netfabb.com/downloadcenter.php?basic=1. That can fix many issues.

makerbeck - Yes, just get a ruby plugin for exporting STL files. Alternatively, you can send me native sketchup files you want printed and I can do the export from Sketchup pro.