This week will see the iPhone released in Guam, and expand to two additional carriers in Singapore. GTA TeleGuam has announced that it will launch the iPhone 3GS and iPhone 3G in Guam on Friday, December 11th, as it will offer the iPhone with any existing MPULSE wireless subscription plan and a two-year contract. Customers will be able to pre-order the iPhone beginning today either online through the company’s web site or at any of its retail…