Can be found on their community weblog:
http://inkscapetutorials.wordpress.com/
Thanks to Ponoko!
http://youtu.be/x0LAmMZ_g34
http://youtu.be/ZYx1ICc-zGI
How to trace an image in Inkscape:
http://picasaweb.google.com/ironhandrail/RasterToVectorFileInInkscape?authkey=Gv1sRgCM74rsTM-6qbYg&feat=directlink
How to make a gear in inkscape:
http://picasaweb.google.com/ironhandrail/InkscapeGearTutorial?authkey=Gv1sRgCInY_NKE9c3YTQ&feat=directlink