This text on MSDN helped us out a lot so you should take it as a good read. Creating a WSS site is a clear-cut case, we enabled anonymous access so everyone can get to is and supplied the “ADProvider” as a Membership provider name. Then you need to edit the web.config document of the site you created (in IIS > root of the site).
<add name=”ADService” connectionString=”LDAP://domain.com/Ou=users,DC=domain,DC=com” />
Inside the <system.web> and after the <authorization> tags you need to specify your connection.
<add name=”ADProvider” type=”System.Web.Security.ActiveDirectoryMembershipProvider, System.Web, Version=188.8.131.52, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a”