Apple will likely have another hit on its hands with the upcoming release of the iPhone 3G S, as the company has sold out of its allotment of pre-order units for the June 19 launch day.

The company said those ordering after June 13 won't receive a unit on launch day, and may have to wait up to one to two weeks to receive their smartphone. AT&T, the exclusive carrier of the iPhone 3G S in the United States, and Apple have set aside an uncertain amount of units for customers to buy at retail locations when the handset is released.

The handset looks almost identical to the iPhone 3G, but it beefs up the processor to make the smartphone faster. The iPhone 3G S also has an improved camera that can record and edit videos and the ability to dial contacts with voice commands; there's also a digital compass that can integrate with mapping services for easy navigation.

The new iPhone will also be able to access 3G data connections of up to 7.2 Mbps. This dovetails with AT&T's recent announcement that it will boost its mobile data network to accommodate faster smartphones like the iPhone 3G S.

Apple and AT&T did not reveal how many pre-order iPhone 3G S handsets were sold, and some industry watchers think the companies will have a hard time matching the iPhone 3G's launch, which sold more than a million units in three days. Existing iPhone users will be facing a higher price tag to upgrade, and the 3.0 software will bring many new features and capabilities to iPhone 3G users.

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