I would like to install Parallels so I can use XP when needed. I don't have any A/V on my Mac and would prefer to not run any. Is there a possibility that a virus can effect XP while running Parallels.
Yes. Anything that can happen to Windows XP (including viruses) can happen under Parallels.
You are especially vulnerable if you use Internet Explorer, e-mail such as Outlook or Outlook Express, or Microsoft Office products, like Word, that you share with others.
Personally, I installed a free A/V program from the www.grissoft.com website. I liked it so well that I uninstalled Norton A/V from my Dell and used the Grissoft product there too.