Project Photofly is a program and a web service, which lets you convert a series of photos of an object into a 3D mesh.

I gave it a quick test.

I made around 50 photos of a small double headed figure (around 20 cm high) and used the tool to create a 3D mesh from it.

This is the result:

Here is one of the photos:

I'm really surprised how easy it was. After reviewing the photos (and rejecting a couple of them becouse they were too dark) I just imported them into the Autodesk tool. The photos get uploaded into the cloud and after a short while the result can be downloaded. And the result was great! I didn't do any manual editing in Photofly whatsoever, the photo/camera positions where all calculated correctly. After exporting the mesh (it contains textures too, but for 3D printing I'm not interested in them) I loaded it into netfabb Studio. The mesh was pretty much complete, only one bigger hole under the chin where I didn't provide enough info with the photos it seems. Besides that there were only smaller holes, all of which could be automatically fixed by netfabb. I just had to cut off the base and now I have a great watertight 3D model.

Really promising, given that was my very first try.

Here's a video showing how you should take the photos: