This is probably not directly related to computer manageability, but I will gladly answer this one. What you are talking about is generally referred to as computer clustering, where you take a lot of computers and make it look like a really big one. Probably the best known software to do thison Linux is Beowulfand Microsoft does havethis feature in "Microsoft Windows Compute Cluster Server 2003", but there are many more. Wikipedia articles can probably get you started.
Hope this helps,