That is my first thought too.. However we have some very PITA people who would loose too much functionality not having full outlook app since not all of our Exchange servers are 2k3 yet. However with exchange 2003 you can almost virtually do everything that the client can minus offline folder use.

My plan in the future once all servers are exchange 2k3 is to Proxy RPC over Port 80 for outlook communication. That seems like a nifty feature of Outlook 2k3/Exchange 2k3