Beginners Guide to 3-D Printing

My guide to highlight some techniques and amazing prints/projects using this emerging technology.  The 3-d printing revolution is really taking hold and more private individuals, hackerspaces, and schools are acquiring these amazing tools. 
Brief Overview:
3-d printing is the act taking a computer generated model and having it created into a three dimensional object of a particular material.  Mostly, this is done though an addative process of layering plastic until the model is created.  Other methods include extruding other material like frosting or clay, and another using light to harden resin into the desired shape.  
Software & Design:
Many types of software can be used to create the 3-D models and export the required .STL files that it seems most printers work with.  Each printer has is own specifics but in general: you'll create a digital  3-d model, watertight it, and export it as usable code.  
http://sketchup.google.com/
http://www.blender.org/
http://www.123dapp.com/
and many more...
Printers:
Many price ranges and print resolutions exist.  Do your research to find the one that's best for you.  
http://www.makerbot.com/ 
http://www.solidoodle.com/
http://pp3dp.com/
http://www.objet.com/
http://www.mbot3d.com/ 
http://www.ultimaker.com/
http://cubify.com/
and many more...
.Orgs and Links:
Please feel free to let know of some of the great groups I'm missing here and I'll add them.  Searching through Instructables, Hackaday and other maker/hacker blogs is also very useful.
http://reprap.org/wiki/Main_Page
http://www.thingiverse.com/
http://www.3ders.org/
Pay per Print:
Why spend a thousand bucks on your OWN printer when you can get e-mail files and get a model in the mail in a short time.  
http://www.ponoko.com/
http://www.shapeways.com/
and others...