RADIUS implementation

Hi,
i want to implement radius server in a small network.
I am still not sure about some things .
1) Can i configure Windows hosts to authenticate the user through the
radius
2) What are the steps to configure a mail service to use radius

And should the mail service use radius or i should just reconfigure
the pam module ?

I know that the questions sound stupid , but at the moment i have no
idea how everything should look like.

I am using freeradius 0.9.3.

thanks in advance