Please try all of the steps in the link below to make sure your Vista/XP network is setup correctly. Note the LLTD requirement for Windows XP machines and be sure to "Add a LOCAL Printer" when adding the printer on the Vista machine.:
Hope this helps.
I have a printer hooked up to a desktop running XP and i want to set up wireless printing with my vista laptop. the laptop will recognize the printer, but when i try to access it it tells me that access is denied. ive done everything i can think of, the workgroups are the same, ive got printer sharing set up, and its not a driver issue because i can hook the USB to my laptop from the printer and it works just fine. so some help would be nice