1.) From the Home screen, press MENU, and then tap Settings > Accounts & sync.
2.) Tap Add account > Exchange ActiveSync.
3.) Enter the Exchange ActiveSync account details, and then tap Next. Your corporate Exchange Server must support auto-detect for the phone to automatically set up the Exchange ActiveSync account. If your corporate Exchange Server does not support auto-detect, you will need to enter your Exchange Server settings after you tap Next. Ask your Exchange Server administrator for details.
Computors will confirm with you the exact settings to use.
4.) Select the types of information you want to synchronize, and then tap Finish setup.
Please note this guide is specific to Android 2.2 on the HTC Sense Platform. Instructions may vary slightly on other devices and other versions.