Free ADVIS Page Header is a customizable replacement of the default SharePoint Portal Server page header, including a Login Button for anonymous users. The Page Header Web Part allows you to show only those page header elements you want: 

Show/hide a portal image on the left side, linked to the portal home. Show/hide the My Site link with either a custom title (i.e. "My Homepage") or the logged in user name as title. Show/hide the Site Settings. In any case, the Site Settings link is only shown for users logged on as portal administrator. Show/hide the Help link. Show a Login Button ("Sign in") for anonymous users.