Windows (upto and including Vista) supports only PC/SC v1.0.  As a part of Windows Vista, there is a standard USB-CCID class driver in-box.  This means that any USB Smart Card reader which is USB-CCID compliant, will not need any additional drivers - they just work when plugged in.  To get a Windows Logo for the Smart Card Reader and the corresponding driver to be on Windows Update, one has to comply with the WHQL logo program.  They wll also need PC/SC test cards for the same which can be obtained from PC/SC workgroup.