The iPhone can be configured with almost all standard e-mail accounts including
the free ones as gmail,. Mac, AOL or Yahoo or one of you own domian via POP3 or IMAP
and even Microsoft Exchange. I want to emphasize the use of e-mail
account with Yahoo as this has an advantage that you should consider.

It’s pertinent to explain a few concepts to understand this advantage. There are two paradigms in the way that your mail is downloaded to an e-mail software.

PUSH:
The e-mail is pushed from the e-mail server to your e-mail software and
therefore you can see the e-mail you receive instantly when a new mail is
arrived on the server. This means that the server communicates with
your iPhone whenever you receive an e-mail.

POP:
The e-mail is extracted from your server and therefore your e-mail software
is the one who has to communicate with the server to extract your messages. This
e-mail extraction or downloading can be done manually or can be configured
on the e-mail software to perform it regularly (every hour, every 30
minutes, every 15 minutes, etc.).

You prefer PUSH or POP?

If you are of the ones that likes to check e-mail or constantly or you need a 24/7 e-mail support, the good news is: To have “push” on your iPhone,
you just need to create a Yahoo e-mail account or use the one that you already have . With Yahoo mail is not necessary to check if you receive new messages, as they will be automatically pushed to your iPhone.