Have you had a look at either -
Outlook/Exchange Configuration
GP Tips and Tricks, under Miscellaneous #4

??

I am assuming you meaning Outlook 2007 and not Exchange 2007?

[Addendum]
Note: Where he defines the ADM File to be:
KEYNAME "SoftwarePoliciesMicrosoftOffice11.0OutlookSetup"
HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\Setup

And once deployed in GPO, it goes to: HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\11.0\Outlook\Setup

You should be able to replace that with:
KEYNAME "SoftwarePoliciesMicrosoftOffice12.0OutlookSetup"
HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\Setup
[/Addendum]

HTH,

Kent