In one of my projects, there's a requirement to change UI for Anonymous User. Sharepoint Services by default, display all the functionality to post new item, edit, etc, like in the List/Item Toolbar. And if user is not authorized, than there's screen to request access. This may be good for internal user, but if your Sharepoint is exposed to Internet for anonymous user. This feature looks weird. So, the workaround for this is to hide this toolbar.
What you need to do is editing the XML Schema/Template for each list. You can see list of existing templates in SPS at folder C:\Program Files\Common Files\Microsoft Shared\web server extensions\60\template\1033\STS\LISTS. Below is example definition for announcement: