With Nokia going for Windows mobile OS, the stage is set for a battle among google, Windows & Apple. Nokia which has seen a declining market share in the recent days, has announced windows mobile OS based phones. Google’s android is being included in most of the phones nowadays. Fearing this, Apple seems to be going for cheaper iphones. Also Hp has purchased palm, with this Palm OS is also going out of picture. RIM’s OS is used on RIM Blackberry phones. These 3 mobile OS will govern the mobile world in the coming days. There is a fierce competition between Apple & Google. Apple’s app store is a USP for Apple with billions of downloads. Compared to this google’s Android app store is far behind.