MODELING ...
Blender powerful free 3d modeling application nurbs and polymesh and everything else
Pepakura simple cheap 3d model pattern maker
Milkshape simple cheap 3d modeler good for low-poly work
Secondlife Virtual world fantastic for prototyping installations and designs
Secondlife LSL Reference reference for linden scripting language, lots of useful cut and paste code
Secondlife info by Torley Torley Linden is one of the makers of secondlife, his youtube videos are fast paced and useful
TurboSquid 3d model repository, some are free most are pay
Sketchup googles free 3d modeling application, has Ruby API built in
CODING ...
Notepad++ powerful free text editing application with many programming language lexers
Ruby my coding language of choice, easy to learn, read, and works with sketchup
Pragmatic Programmers guide  Pleac  Zenspider three resource links to Ruby syntax, I use these often
Sketchup Ruby API info on how to use the builtin Ruby API in Sketchup
Ghostscript free postscript viewer, to view Pointsware output files you need this installed, GSView helps too
Imagemagick free commandline image manipulation application, can be called from Ruby
Tesseract googles free OCR application
Amaya free html builder, works with SVG and makes compliant web code
w3c world wide web consortium main page, tons of useful stuff for all things standardized web
w3c html tags reference world wide web consortium html tags list and specs on how they all work and are used
DOS shell command reference all that stuff you do with your mouse you can do at the commandline, or with a script!
SVG Scalable Vector Graphics format, like postscript but XML based for the web
PHP A server side scripting language for writing web applications, easy to learn and hybridizes into HTML
MAKING ...
Instructables someone already made that thing you want to make, and here are the directions
USPlastics get all your plastic raw materials from here, great prices and will sell small quantities
Grainger lots of basic parts and materials, not the cheapest
Automationdirect motors actuators steppers servos, make it go!!!
Buildit plans to make stuff that makes stuff
Arduino affordable microcontrolers to control that stuff you made