I second David. SBIG (I don't know what brand you are looking at, but SBIG is my only experience
) will work fine on XP with the right PCMCIA parallel port card. USB to parallel adapters won't work.
have a look at these threads. They describe the card I use:
http://www.iceinspace.com.au/forum/s...t=LPT+Parallel
http://www.iceinspace.com.au/forum/s...t=LPT+Parallel
Al.