Running XP on a Vista system?

I am running Vista Home Premium.
I also want to run XP Pro.
I thought the answer would be to use Microsoft Virtual PC.
On downloading Virtual PC you're told that Vista Home Premium doesn't support it.
I know you can run a duel boot system, but you have to install XP first.
For various reasons I don't want to do this.

Is there an alternative to the Microsoft Virtual PC.

Thanks.