The i-Phone, sometimes also rendered as the i Phone, is a mis-rendering of the Apple product, the iPhone.
Apple renders the name of its combination iPod/PDA/web and email device/mobile game station/phone with a lowercase “i” before the word “Phone,” but without a space between the two elements of the name. Thus the correct rendering is “iPhone,” rather than “i-Phone” or “i Phone.”
To learn more about the iPhone and how to use it, read these articles:
Apple i Phone