If you including iPhone users who want a presence long enough new OS with support multitasking features. The Apple company after needs respond iPhone users, with release new system operation on iPhone OS 4. iPhone OS 4 including new system operation, which is evolution from development iPhone 3GS.  This iPhone OS 4 experienced improvement from various aspects, and equipped with interesting features.

With multitasking feature, you can run more than one application with simultaneously .You can also make phone calls with play games and read email.  iPhone OS 4 can use to make folder which can facilitate applications management appropriate user needs .This iPhone iBooks after provide search menu, purchase, and Book reading. With this facility, you can also download online applications. As iPhone users, you can get income from facility iAd advertisement on mobile phone.