AT&T to sell Sony Ericsson 8.1 megapixel Cyber-shot

* Cyber-shot to sell for $179.99

* 8.1 megapixel camera compares with iPhone's 3 megapixels

NEW YORK, July 15 (Reuters) - Sony Ericsson said AT&T Inc (T.N) will sell its latest Cyber-shot camera phone, giving the venture of Sony Corp (6758.T) and Ericsson (ERICb.ST) a chance to boost its weak U.S. market position.

Sony Ericsson said the C905a Cyber-shot phone, which has a 8.1 megapixel camera in comparison to iPhone's 3 megapixel camera, would go on sale July 19 for $179.99 after a rebate to customers who sign a two-year service agreement with AT&T, the second biggest U.S. service provider.

Carrier agreements are key to a phone's success in the U.S. market where operators tend to shoulder part of the sales price for customers who commit to a long service contract.

But in a market where touchscreen controls and computer-like keyboards are often the most coveted features, Sony Ericsson has had a hard time keeping up with rivals such as iPhone maker Apple Inc (AAPL.O) and BlackBerry maker Research in Motion (RIM.TO).

According to research firm Strategy Analytics Sony Ericsson fell to ninth place from eight in the U.S. market in the first quarter, behind new competitors such as Apple and traditional rivals like Samsung Electronics (005930.KS).

"Sony Ericsson's been struggling in the U.S. for four or five years," said Strategy Analytics analyst Neil Mawston who said that Sony's problems in the U.S. are similar Thor those of global market leader Nokia (NOK1V.HE), which ranks fifth here.

"Their challenges are identical to Nokia, a lack of presence at the top four carriers and a lack of presence in high growth categories," he said. (Reporting by Sinead Carew; Editing by Derek Caney)