writes "Researchers at Oxford University have produced a Java-based x86 emulator that they hope will be useful in testing applications and learning about viruses without damaging the host, utilizing the robust sandboxing that Java provides. They have an online demo available that boots DOS and has some games to play. Being purely Java, this emulator should be able to run on almost anything, including cell phones."
The code is not yet available outside the Oxford community; the developers are said to be working on a suitable general license. In the meantime the code can be licensed on a case-by-case basis.