Change your account options
Email checking frequency = how often your phone
checks for changes to email, contacts, and calendar.
Amount to synchronize = amount of email to keep on the phone by age.
Send email from this account by default = When you click an email address
inside a webpage or somewhere else this will be the default address you send from.
Notify me when email arrives = you will be prompted by the phone when you get new email.
Sync contacts from this account = your exchange contacts will sync with your phone.
Sync calendar from this account = your exchange calendar will sync with your phone.