Push email on iPhone is provided by network company like AT&T or by iPhone.

Thanks

Thank you for your quick reply.
If you are an iPhone owner what do you think about the battey life?
I have an iPod touch and I am not very much impressed with it's battery life. Is it same on iPhone?

Would you please say a few wards about iPhone's push email. Does it work just like SMS? You get email instantly and do not have to wait.