Home systems normally use WORKGROUPS, and not a Domain - - a real Domain Controller(DC) requires a Windows Server {2000, 2003, 2008}, another system to run it and lots of $$$$
Most of us never need a DC - - why do you think you need a Domain?
so WHY doesn't simple filesharing work for you? I have XP/Pro sharing with Linux, Mac OSx, and even an old boat anchor link Win/98se - - no domain is required.