DXKeeper, the logging component of the freeware DXLab Suite, can directly print QSL cards (or QSL labels that can be affixed to QSL cards), and works well on Vista. Here's an example of a generated QSL card:
http://www.dxlabsuite.com/dxkeeper/QSL.jpgCards can be printed "4-up" on 8.5"x11" card stock.
73,
Dave, AA6YQ