The built in Smart Card logon requires a Windows Active Directory domain to enable smart card logon to a PC. For work group or standalone PCs there are several Single Sign On applications that enable smart card based logon without a domain or even a certificate authority. Two solutions we can recommend are:
Sphinx - Open Domain Solutions. A commercial vendor of Single Sign On focussed on smart card. This solution has an excellent management server, and is highly customizable.
EIDAuthenticate from My Smart Logon is a free, open source solution that allows you to use a self signed certificate to encrypt the password of a stand alone user account.
Many other commercial Single Sign On applications support password login protected by a smart card as well.