I have to say I really like the idea. grabbing the task GUIDs right out of outlook, cool beans.
I'm sure a custom app can provide much more flexibility for you, but I have to wonder...

wouldn't MS Project do much of the same thing... also, if it is just a matter of getting your calendar events (time worked) up to your boss, can't you just setup a public calendar on the network that everyone updates (only able to see thier own of course)?
Just a thought. I still like the GUID aspect of talking with outlook....
We need to do some outlook 'manipulation' in the near future, I may look at doing it this way instead of relying on APIs (and hoping they exist)

Would you have any recommended sites or code or declares that might get us in the right direction?