Single Sign On (SSO)

Hello,
I am new to Identity management systems & .Net framework 3.0, and I have been going through the documentation for MIIS 2003. My objective is to implement single sign on for all applications (Microsoft, Non-Microsoft, Web & desktop) in my company.

Recently, I cam across an article on .Net framework 3.0 which suggested that Windows Card space can be used for single sign on. Has anyone used Windows Card space for SSO? If yes, then what are its advantages and disadvantages over MIIS 2003? And which is the best approch to achive SSO?

Thanks & Regards,

Rajiv