Nokia N91 Belongs to N series and it has builtin 2Megapixels of camera and in the old version it has 4GB inbuilt memory and in the new version it is upgraded to 8GB built in memory. It can store more than 2600 songs approximately. The opeating system in Nokia N91 is symbian series 60. The new version of N91 8gb and avail wifi facility. The new version has builtin 3megapixels of camera and it is also symbian series 60.