Proteus:
http://www.ieeproteus.com/descarga.html

Crocodile:
http://www.crocodile-clips.com/

Crocodile Elementary
http://www.crocodile-clips.com/gpv70/Demos/elem.exe
 
Cocrodile Technology demo
http://www.crocodile-clips.com/demo_file.do?id=84

IC-prog:
http://www.ic-prog.com/

MPLAB:
http://www.microchip.com

Orcad completo, versión demo
http://www.cadence.com/downloads/orcad/files/ORCAD157Demo.zip 

Información sobre OrCAD en general:
http://www.orcad.com

Lattice ispLEVER
http://www.latticesemi.com/products/designsoftware/isplever/ispleverstarter.cfm

Xilinx ISE-Webpack
http://www.xilinx.com/ise/logic_design_prod/webpack.htm

Electronics Workbench:
http://www.electronicsworkbench.com

ElectronicsWorkbench multisim
ftp://ftp.interactiv.ni.com/pub/interactiv/demo/MS9StuDemo.exe