I initially did this article on my web site at uC Hobby but figured I would give it a try as my first instructable. Let me know what you think.
First let me say that this is dangerous. Your PC power supply should have protection from shorts but you are sure to loose any open files not if, but when you make a mistake on your breadboard. Also the PC power supply can output a great deal of current so things can get out of hand quickly. In fact, the more I think about this, the more I realize it is a bad idea.
The first two pictures show the finished product. A PC power plug with long extension wires that reach my microcontroller breadboard. The PC provides +12 and +5 VDC.
Step 1: Find parts
Step 2: PC power connections
Step 3: Connect extension wires
Step 4: Solder the connections
I like to strip a long section of the insulation, wrap, solder then trim about half the length. This makes it easy to ignore large solder blobs at the end of the connection. You don't need a 3/4 inch connection after it is soldered.