80 or 8080 port in WinXP

How to open 80 or 8080 port on WinXp Pro? I need this port for Xitami. This program give me an error “Cannot open 80 port”. Tell me what`s happend and how to open this port manually. Or.. if u know another program like as Xitami tell me please. Please mail me at admin@soround.com

Thanks