Apple executive Phil Schiller tweeted that a white iPhone will be avaliable in the spring (finally!). Apple first announced a white iPhone in June 2010 along with the black iPhone 4, but had only too many delays. Apple said that the white paint leaked through the phone and affected the rear camera, and the many delays were to fix this problem. Some may say there will be yet another delay, but I don't think so. After all, the white iPad 2 has a rear camera and it worked out fine...
