combining pc’s

OK, i have 3 pc’s that I want to combine into 1 processing machine. All boxes have 1g of ram and at least a 1.8g processor. My question is this; how do I make all 3 pc’s act as one? There is a way to do this but I can not find any info on the interweb how to do it. This is an exercize on improving multiple processer computing using separate machines to solve a single solution to the assigned task. I do not care if it is for gaming or finding life elsewhere in the universe or finding the DNA sequence of cancer. All I want to do is combine 3 computers into 1. So I challenge all of us techno freaks to show how to run 3 to whatever pc’s as one. Do you dare to take the challenge?