So you want to push your users towards that shiny new web portal. Using a GPO seems the obvious route.
Here's how.
Use a GPO to update a Registry key in the following location.
HKCU\Software\Microsoft\Internet Explorer\Main
Here are the key details for the first tab/single tab.
Action : Update
Hive : HKEY_CURRENT_USER
Key Path: Software\Microsoft\Internet Explorer\Main
Value name (default unticked) : Start Page
Value type : REG_SZ
Value data : http://www.google.co.uk
If you want to add a second tab...
Action : Update
Hive : HKEY_CURRENT_USER
Key Path: Software\Microsoft\Internet Explorer\Main
Value name (default unticked) : Secondary Start Pages
Value type : REG_MULTI_SZ
Value data : http://www.theregister.co.uk
You can set the policy to apply once and not reapply if needed as usual with a Group Policy Object.
