don't use it but google says
The iPhone has push email, but it's pot luck as to whether or not your email server actually supports it. If it doesn't, chances are you've resorted to the battery and data-draining "check every 15 minutes" option. Well, here's a quick and easy way to hook any account up with push email that lands on your iPhone in seconds.
iCloud
The trick is in using iCloud. "But wait," you shout. "I don't want to use iCloud! I want to carry on with the email address I've had for 15 years, that everyone knows!"
And the beauty of it is that you can. So...
1. Launch the Settings app on your iPhone and tap the "iCloud" button.
2. Sign in using your Apple ID.
3. Slide the "Mail" switch to "ON."
If this is your first time using iCloud's mail sync, you'll be guided through a process to set up an "@me.com" address. You need this address, so don't skip this part. However, you won't ever have to give it to anyone, so don't worry if your name is already taken and the address is a bit obscure. It's for your use only, so anything will do. If you already have an "@me.com" address, get it ready for the next bit.
4. Go to your email server and set up a forwarding service that copies all your incoming email to your new "whatever@me.com" address.
This could require a little research as each one is different, but most every email server supports forwarding, including Gmail, Yahoo! and Mail.com. If you use your own hosting and have access to cPanel, use the "Forwarder" option in the "Mail" section.
NOTE: A forwarder doesn't affect your existing email account. That carries on working as normal, so don't worry about forwarding message on to another account. What happens now is that you'll effectively get a second copy of your email coming through to your "@me.com" email address. It's this copy of the email that Apple will happily and speedily push to your iPhone.
5. Launch the Settings app on your iPhone again and tap the "Mail, Contacts, Calendars" button.
6. Tap the "Fetch New Data" button and slide the "Push" switch to "On." Leave "Manually" ticked for you non-push email accounts.
7. Tap the "Advanced" button to apply specific options to individual email accounts. For example, if you've a Gmail account already set up, switch that one to "Manual," and set iCloud to "Push."
Now, whenever you get a new message on your existing, non-push email, it's immediately forwarded to your new "@me.com" address and pushed to your iPhone.
As far as everyone else is concerned, you're still using your existing email address. You just don't need to crack open your iPhone as often to fetch your mail.