Hi, this is my first time on this forum and I would really appreciate some help. I have been spending time in Israel and purchased an iPhone 3GS over there with cellcom carrier. I do not know if it is unlocked, can i find out before I arrive to the US? Also how would I go about using it in the US whether it is or isn't locked. Basically, what are my options? I will use ATT as a carrier in the US and hope I am not locked out of any services like 3G, or from being able to install new versions as they come out. Lastly does anyone know if Apple in the US will cover the warranty for the phone purchased in Israel? Thanks in advance!!