Remote management for Windows system upgrades

I'm looking for some remote management tips I can use in my Windows shop. I have Windows Server 2003 servers and Active Directory on a single domain. We have approximately 100 client computers, all at one location. I am upgrading all computers from Office XP to Office 2003.

My project:
I want to install Office 2003 and all updates remotely without going to each machine.

My progress:
I tried the method of creating a network share with a compressed CD image and chaining the updates with OHotFix.exe, but the installation and updates both fail if the users are not administrators of their local machine.

The other method I tried was to use Group Policy and assign the installation. This has worked well, but the method does not support chaining, so I cannot run the updates. Once again, I can't just supply a path for users to run the updates, because they aren't local admins.

So, can you send out updates for Office with Group Policy? Are there other methods out there that you all know about and use to get this done fairly easily? Would WSUS be a good solution for this?