Not only will your iPhone synchronize your email using Exchange ActiveSync, but you can also take advantage of the Contact syncing capabilities built into the iPhone and ActiveSync.
When you update a contact on your computer or on your iPhone, the changes are automatically synchronized. This ensures that you always have the most updated information wherever you are accessing your email. And with ActiveSync Direct Push, these updates and synchronized automatically from wherever you are as they are made. You never have to worry about updating your contacts in multiple places ever again.
Integration between iPhone applications allows you to use contact information to find addresses using Maps or GPS, or call up directions to confirm how to get somewhere. So with automatic Contact synchronization, you’ll never get lost when you’re going to meet someone. You can also use contacts to initiate SMS messages, or even attach vCards to email messages.