xsane doesn't do any actual color calibration, just some heuristics for color correction. There's also no fancy hardware involved for scanner calibration (that's required for calibrating printers, though) - all you need is to purchase a "known good" color chart printout off of the web (or eBay) and scan it then process the resulting TIFF w/ Argyll to generate an ICC (assuming its one of the charts that Argyll has the "correct" color values for, otherwise you'll need to buy a chart that comes with a "correct" model on a CD/USB alongside it or else use a "good enough" color values chart that someone uploaded).