File Sharing: Physical Vista and Virtual XP

I have a Virtual Machine installed on my physical computer. The Virtual PC
runs XP and the physical PC runs Vista. I have read that the file sharing
options in the Virtual Additions package are not the best. The advice I have
received, on these boards, is to use Vista's built-in file sharing.

So, can anyone offer advice on how to configure my Vista computer to share
files with my XP virtual computer? I tried reading Vista's help pages on
sharing, but it soon became complex. Surely this should be fairly easy, right?

Thanks.