Networking a Vista Computer with a Windos XP via wireless?

I have a wireless network at home with a wireless linksys router that is connected to my main pc using Windows XP, I have a second desktop with a wireless USB device using XP also. Both of these computers are connected to a home network that I have set up and have no problems with file and internet sharing. I recently bought a new laptop that is wireless ready and it came with Windows Vista home edition. I connected to my home network, entered int he security code and the laptop connects fine to my network automatically and goes online fine. The problem I am having is, I cant seem to perform any file sharing with this laptop. When I go into the network section it is only showing the laptop and neither of the 2 desktops using XP which are named differently on the network. This is my first time using Vista so I am wondering if I am missing something. The main desktop has the my docs section set for sharing also.