[Rootstonian]

I would run the network wizard on the XP box and make sure File and Printer sharing is turned on. Also, as stated above, you want the XP box to have the same Workgroup name as the Vista machine.

On Vista, I just turn on File and Printer Sharing AND Network Discovery. I think it'll (Vista) will ask you want kind of network you want and you should choose "Public". This allows other computers on your network to see each other (trust me, I just did this last weekend).

On your drive on the XP box, makes sure you share it. Then, on the Vista side, I would just map a drive letter to that share (so if you called the drive on XP, xp_shared, you would map to \\xp_computers_name\xp_shared)

Do you need to share the ENTIRE drive? Not only could this be a security risk, but depending on the size of the drive, setting permissions on all the folders could take a while