How to become a iPhone designer?

How to become a iPhone designer?

It defiantly helps if you write letters to the design team, if you suggest some good ideas that they would like to implement, they would like you more

Since this is all done in-house (at the company) I doubt you could get a solid 'in' with them. They will not be open to ideas spitballed at them in a letter, there's always the liability issue of someone claiming that they stole your designs - hence they won't even read letters offering design fixes.