FACTBOX-Rivals who may be hurt or helped by iPhone

NEW YORK (Reuters) - As Apple Inc. starts selling the much-hyped iPhone on Friday, rivals will scramble to keep up their share of the highly competitive mobile phone market. Some hope the excitement of the music and video-playing device will boost their own sales.

Below are handset makers and their U.S. carriers who have the most to gain, or lose, from the iPhone, which goes on sale in the United States for $500 and $600 through AT&T Inc..

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SONY ERICSSON: Sony Ericsson makes the Walkman range of phones. AT&T gives away the W300i model, an older clamshell phone with a music player and camera.

Sony's upcoming W960 sports a touch screen and will let users shuffle through their music collection by shaking the phone, but no U.S. release date has been set.

LG ELECTRONICS: LG's Chocolate, a music phone sold by Verizon Wireless for $99, has dedicated music player controls on its front and a slot for extra storage space. Verizon Wireless is owned by Verizon Communications Inc. and Vodafone Group Plc.

Muziq from LG will be sold by Sprint Nextel Corp. for about $100 in July. It has a music player and a button on the side that lets users listen to music while they send text messages.

LG's Prada has a touch-sensitive screen, like the iPhone, but is not yet available in the United States.

SAMSUNG ELECTRONICS: Samsung's Upstage is sold by Sprint Nextel for about $80. The phone has music controls on one side and a typical phone keypad on the other. It has a slim case with a built-in add-on battery.

NOKIA OYJ: Nokia's most powerful media phone, the N95, is doing well in Europe but has yet to hit it big in the United States, where it is not sold through a carrier but at Nokia's stores and Web site for $749. It has a 5 megapixel camera, built-in location-based global positioning system (GPS), a music and video player, and extra storage space.

5300 XpressMusic from Nokia is a popular music phone sold at T-Mobile USA, owned by Deutsche Telekom, for about $50, with dedicated music player buttons, a 1.3 megapixel camera and extra storage.

HELIO: Ocean, designed and sold by upstart Helio, has a mini "Qwerty" keyboard and a standard numeric keypad hidden under a screen that shows integrated instant messaging and text messaging. It supports high-speed networks, GPS, can play music and has a 2 megapixel camera.