Microsoft Corp. said a new version of its OS for mobile phones will be available on handsets by the end of the year as part of a plan by the company to strengthen offerings in the consumer market. The new OS from the Redmond, WA, company, called Windows Mobile 6.5, is designed to incorporate enhancements that started to become common on sophisticated "smartphones," like better Web browsing and the ability to operated phones with touch-sensitive screens using a single thumb. Microsoft CEO Steve Ballmer announced the new products in a keynote speech at a mobile industry conference in Spain on Monday. The improvements are important for Microsoft to stay competitive in a category that experienced a major influx of investment and innovation in the past two years from rivals like Apple & Google. Microsoft executives concede the company has focused too much in recent years on the business market for mobile phones, while neglecting features that's