Internet Connection Sharing

I recently built a new home PC since our old one died after 6 years of
service. My situation is somewhat unique. I am running Vista Business on the
new PC, but I have satellite internet that there are no Vista drivers for,
so I am running a XP Pro machine, sort of as a router. I have ICS enabled on
the XP machine, but can not get the Vista box to see the internet. I can
access files back & forth between both machines, but for whatever reason the
Vista box will not connect, & the pretty little diagram even shows no net
connection. Is this a common problem? In the past ICS was very easy to get
to work on most all platforms including Ubuntu Linux. Am I missing some
setting somewhere? It almost has to be something simple that I am
overlooking. Please help me if you can, my wife is going nuts without her
email!!!

Thanks
Brian