An appleII emulator has been released for xbox , it's 100% legal (not build with MS SDK). It's using linux to boot.
http://www.consolevision.com/dcgrendel/ (link dead)
Please see this link instead.
EDIT by Admin, fixed links on 20th July 2003
UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 (CK-SillyDog)