Carphone Warehouse sold out of 8GB iPhones in the U.K. within days of dropping the price, and now it is fresh out of 16GB models, too. The higher capacity combination iPod and smart phone sold out even though it was still at its regular price, and may be another indicator that a product refresh is on the way, according to The Guardian.

O2 and Carphone Warehouse dropped the price of the 8GB iPhone to £169 from £269 in April and quickly sold out of the lower capacity model. Neither model is being restocked, adding more credibility to the rumors that new iPhones are only weeks away.

Analysts are speculating that Apple will release slightly redesigned models with faster 3G wireless data capabilities, but at the same 8GB and 16GB capacities found on current models.

New iPhone models could come as early as Apple’s World Wide Developer Conference in June, according to some analysts. If Apple introduces new models at the conference, however, the company could delay releasing them until the end of the month to coincide with the launch of the App Store and iPhone Software 2.0.

The App Store is Apple’s distribution system for authorized third party applications for the iPhone and iPod touch. Users will be able to access the online store from iTunes and from their handheld device, too.

iPhone sales in Europe have not matched those in the U.S. where the handheld has proven most successful. Upgrading the device to support 3G, however, could be just the ticket to boost overseas iPhone sales.