Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
How do you add an MSN email to iPhone mail browswer?

Do you mean specifically an @msn.com address or any MSN address, like a @hotmail.com address?

I know for an @hotmail.com, one can simply choose the 'Exchange' account setting under the Mail app.

This Apple support page will walk you through the setup.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.