You don't need sambadirectly to print to a windows machine. When you add a printer using Slack's method (probably cups) you will install a remote printer and it will ask for the samba share info during install. Allow the printer to be shared on your XP machine and you should be fine.
I went to their site, and printing howto referred me to this page, so I guess you get to choose which one you want. CUPS and LPR do the samba remote printer (I think they actually just call it a windows printer in the menu)
http://en.tldp.org/HOWTO/Printing-HOWTO/
RO