Drawing, CAD , Flowchart

Electronic Diagrams (-: (:
TinyCAD is a program to help you draw circuit diagrams. It comes complete with symbol libraries to get you started straight away. As well as being able to simply print your designs, you can use TinyCAD to publish your drawings by copying and pasting into a Word document or saving as a PNG bitmap for the web. http://tinycad.sourceforge.net/
(-: (:
Computer Networks.
Network Notepad is a Freeware program for creating interactive network diagrams.
http://www.networknotepad.com/

Flow Charts.
Diagram Designer. Description: Simple vector graphics editor for creating flowcharts, diagrams and slide shows. http://logicnet.dk/meesoft/DiagramDesigner/

CAD Computer aided design.
CadStd is a general purpose, easy to learn CAD/drafting program for creating professional quality mechanical designs, house plans, blueprints, schematics and charts utilizing ANSI drawing standards. The Lite version is free and can read any drawing created by the Pro version. CadStd Lite can export files as DXF so you can share your drawings with friends who have other CAD programs like Autocad.
http://www.cadstd.com/

TIGER CAD:
A completely free, simple technical drawing software (CAD).
Ideal for garden design, mechanical engineering drawings, electrical / electronic, building and room plans, and general diagramming. Output in PDF format for the web. Copy and paste graphics. Create standard symbols to re-use. Scale, mirror and rotate. Accurate scale drawing printing. Drafting tools to compare with pro packages. http://peterhoward42.blogspot.com/2008/07/tigercad.html