Scenario: on a domain network with exchange 2003\2007, when using roaming profiles with different OS and different
Office (2003\2007), outlook is unable to browse Exchange Global address list.

Office 2003 uses a Hidden public folder to download the GAL.
Office 2007 is using HTTP connection to exchange site to download the GAL.
Two options for solving this problem:
A. install outlook 2007 will automatically download the GAL.
B. Manually update the Outlook 2003 with the GAL as follow:

1. Open outlook 2003
2. Go to Tools > Send/Receive> Download Address Book.
3. Uncheck "Download changes since last send/receive"
4. Select the "Full Details" tab.
5. Select "Global Address List" as the Address Book.
6. Click OK.