man with plus sign on phone keypad - what for?

I think it may be if you are already on a call and want to initiate a conference/3 way call.

Actually, that button will add the number you've entered to your contacts. It's what you do, for instance, when you're walking down the street, see someone you know, and don't have their phone number. You get it, dial it into the keypad, then click the "+" with the man by it, and add them to your contacts.

Dustin

You will find the user manual for the iPhone here: http://www.apple.com/support/manuals/

It is suggested reading.

Manual Page 33 - How to add contacts directly from the iPhone, complete with illustration of man with plus sign on phone keypad.

Enjoy your iPhone!