How can I use OCS on my Windows Mobile device?

1. First download OCS Mobile from Microsoft, and save it to your computer so you can install it on your device using ActiveSync.

Application download: Microsoft Office Communicator Mobile (2007 Release)

User’s guide: Microsoft Office Communicator Mobile (2007 Release): User's Guide 

2. Now connect your Windows Mobile device to your computer and establish an ActiveSync connection. If you need the latest version of ActiveSync, you can download it from the Microsoft web site:

3. Once your device is connected to your PC and the ActiveSync connection is established, run the OCS Mobile installation file that you downloaded in the first step. Follow the on-screen setup instructions.

4. Now that OCS Mobile is installed, you will see a new icon on your Windows Mobile device home screen. Select OCS and after it starts, select Options from the bottom right.

5. On the Account tab, enter your information in the same format as in the screenshot below.
* Be sure to use your email address as the sign-in address. 
* You can find the domain\username in CONTROL PANELfirstuse > Users. Click the display name of the user. On the user settings page, click the display name once again to see the username in the Edit User Info window.  It is also the same as your ActiveSync username.

Read the following Knowledge Base articles for more information about your domain and username:
What Is The Exchange Domain And Why Is It Important?
What Is My Username And Primary Email Address For My Exchange 2007/2010 Mailbox?

6. Now go to the Server tab at the bottom. You will use the same OCS server name in both the Internal server name and External server name fields. You can find this information on the OCS page in CONTROL PANEL.

7. Click OK at the top right of the screen. Now you can sign in.