My phone doesn't tell me that I have an email unless I open up the mail app first.

Question

How do I get my iphone to update me that I have an email without having to open the mail app?

Answer 1

Did you try "Fetch new Data" in Settings/Mail, Contacts,Calendars?
Fetch New Data
This setting lets you turn Push on or off for MobileMe, Microsoft Exchange, Yahoo!, and any other push accounts on iPhone. Push accounts deliver new information to iPhone whenever new information appears on the server (some delays may occur). You might want to turn Push off to suspend delivery of email and other information, or to conserve battery life.
When Push is off, and with accounts that don’t support push, data can still be fetched—that is, iPhone can check with the server and see if new information is available. Use the Fetch New Data setting to determine how often data is requested. For optimal battery life, don’t fetch too often.
Turn Push on: Choose “Mail, Contacts, Calendars” > Fetch New Data, then tap to turn Push on.
Set the interval to fetch data: Choose “Mail, Contacts, Calendars” > Fetch New Data, then choose how often you want to fetch data for all accounts.
To conserve battery life, fetch less frequently.
copied from http://manuals.info.apple.com/en_US/iPhone_iOS4_User_Guide.pdf , page 203