I have eventualy found a way to share the printer on XP to Vista using various tips from posts.
- Connect, install and share printer on XP
- On Vista PC, In Printers Click "Add Printer" - Local Printer on LPT1 and install to there.
- Right click on printer icon, go to Properties, Ports, Add port - New port - "\\XPComputerName\XPPrinterName"
I sent this to Epson earlier in reply to an email from their tech team which sent me to Microsoft for a whole lot of dribble not really related.
Hope this helps.