First Wireless Network

I just set up my first home wireless network. I have a Vista Desktop (JASON-PC) and an XP Laptop (LAURIE) hooked up to it, and both successfully connect to the internet. Both computers can see each other (the vista box shows both computers under "Network;" the XP box shows nothing under "My Network Places," but when I "Search for Computers..." and type in its name it shows it under workgroup).

However, I am unable to share files or printers between the computers. If I attempt to access the XP box from the Vista box, it asks for a username and password, and if I attempt to do the reverse, I get an error message ("Jason-pc is not accessible." ). If I try to add my printer (hooked up to the Vista box) on the XP box, I am able once again to find the Vista box under workgroup, but when I type in the printer name and hit next, it says "Windows cannot connect to printer."

I have set several folders and the printers as shared on the Vista box. Any help would be appreciated. I'm sure there's just some simple step I'm missing.