start here: endusersharepoint.com/2008/12/03/… and you will probably have to modify the script to make it do what you want. You can apply .css from a javascript within the page if you don't want to modify the master page. You will just need to know what .css classes you need to modify, and how you want them to look.

For the environment using AD, you can always either use the AD fields or click on the Shared Service Provider from Central Administration (It would say "SharedServices1" or whatever you named it.

You can find some information about Relay for Exchange 2007 here: msexchangeteam.com/archive/2006/12/28/432013.aspx I don't know if you are using Exchange or not, but that would be a good place to start. If you are not using Active Directory, do you have a SQL database of users? You could add a field or table for Email Address and populate it there. The only other option you could use would be to set up a workflow using SPD where you manually enter the email address.