At work, we needed to test out our project on as many machines as possible, but we could not get access to enough machines that we could maul as and when we pleased. VMWare would have helped, but we didn't have enough licenses. Bochs was good but was too slow for practical purposes. Fortunately for us, we found QEMU and it fit the bill quite well. It has been written primarily by Fabrice Bellard and is quite fast and works surprisingly well - we could get an entire installation of Red Hat Enterprise Linux 3 Advanced Server running under QEMU without any problems! For the adventurous, quite a few QEMU-ready images can be found at FreeOSZoo. QEMU also comes with a utility to convert VMWare disc images to the raw disc images used by both QEMU and Bochs. Very cool stuff and highly recommended! Thanks Fabrice!