[CentOS] XEN and PCIPassthru

I have an old windows NT machine, that I would like to virtualize under
CentOS and xen. The problem is, that the machine has an old PCI card that
is used for some sensor control. I tried to google the topic, but there
isn't any useful tutorial, how to do this under CentOS. What I found out
is, that I need a machine that supports the Intel VT-d technology and at
least XEN 3.3. Does someone on this list have any real world experience
with this?