I'm a big fan of using multple Microsoft Virtual PC images, especially for demos and development. My current machine has a second hard disk that is dedicated to images that I use for such work. One of the problems I've run into in the past is getting multiple Virtual PC instances to talk nicely together over a network - regardless of whether the host machine is connected or not. On frequent occasions I've turned up to do demos only to find out that Virtual PC #1 cannot see Virtual PC #2 on the network - even though they are on the same machine! This week I've been putting together a demo that involves 4 Virtual PCs talking to each other simultaneously (showing interop between different vendors). I put in some time working out a foolproof way to get each Virtual PC to talk to each other, and also be able to use the network adapter of the host machine. Read the rest here.