The Apple Worldwide Developer Conference has historically been the event where Apple has announced the latest iPhone hardware, so the recent announcement that this year conference will be held in San Francisco from the 8th June to the 12th June strenghtens the earlier rumors of a June announcement of the next generation iPhone.
Although the rumors around the next generation iPhone probably started around the same time as the current iPhone 3G was launched, they have increased since the announcement of the new iPhone OS 3.0 a couple of weeks back. Since then there has been news revealing references to not only one, but two new iPhones in the new operating system, which usually is a clear sign that Apple is actively testing new hardware on the new operating system.
Recent weeks have also seen the iPhone 3G starting to be sold without a contract, and there are rumors of mobile operators authorised to sell the iPhone to start slashing prices to clear stocks come May time in preparation for the next iPhone to be launched this summer.
We will keep monitoring the market for news and updates on the next iPhone release.