It’s worth saying it again. The iPhone 4 sold at Mobily showrooms is officially unlocked so you can use Micro-SIM cards from Saudi Telecom Company, Zain and other companies. I will just re-post the 3G post here with edits of course.
I have been receiving e-mails stating that Mobily employees are claiming that the iPhone 4 is locked to the Mobily SIM cards. Other employees claim that the next iPhone 4 shipments will be SIM locked. We and others tested the iPhone 4 and we confirmed that it is not locked to Mobily SIM cards. Apparently that was not enough. A friend that went to Mobily in Jeddah said that Mobily employees still insist that the iPhone 4 is locked to their network.
This page on the Apple support website clearly (and officially) states that the iPhone 4 sold in Saudi Arabia by Mobily is NOT LOCKED TO THE CARRIER. Same in the United Arab Emirates with Etisalat and du.
Feel free to print that table and present it to the Mobily employee who claimed that the iPhone 4 is locked to their network.
Arabic version of this post on SaudiMac Arabic Edition.