Here are the steps on setting up your iPhone to sync with Microsoft Exchange.
1. Make sure your iphone is running the iPhone OS 2.0; If not, you will need to install iTunes 7.7 and upgrade it
2. On the Exchange account, check if it is using IMAP. If so, you will need to disable it.
3. Click on the ‘Mail’ icon to setup a new mail account.
4. Choose ‘Microsoft Exchange’
5. Enter in your email address and username/password for the Exchange account.
6. If the auto discovery fails, it will prompt you for the server name.
7. If all information is entered correctly, you should be able to receives emails from your Exchange account.
8. Now, if you want to sync the calander and contacts too. You can do this. On the email account that you createdand under calander/contacts, tap the ‘sync’ button.