what have you done so far?
have you set up the ip address's correctly with the subnet mask or are you using the networking wizard?
to define the ip address's go to control panel and select the newtork connection in question
computer 1 win 7 ip address: 192.168.0.1
subnet mask: 255.255.255.0
Computer 2, win xp: ip address: 192.168.0.2
subnet mask: 255.255.255.0
once the IP's have been defined the computers are now pointing at each you will need to either right click and choose to enable sharing on folders or put the folders you wish to share in the shared folder.
you may also need to make sure net bios over tcp/ip is enabled along with LM hosts again both options can found in the network conenctions where you configured the IP address under advanced - then the wins tab
pretty sure thats it i havent doen it for a while but it worked very easily for me will post back if i remember anything else
