Russian mobile carrier MegaFon has announced that it will begin selling the iPhone 3G in Russia later this year, becoming the second carrier in the country to do so. Last week Vimpelcom announced that it too will begin selling the device later this year; prior reports had suggested that all three of the major Russian carriers — Vimpelcom, MegaFon, and MTS — would offer the device. Negotiations between Apple and China Mobile have reached…