The PlayStation 4 is a long time coming, and it may be revealed well before E3. According to Hiroshi Sakamoto, a Sony executive, the PlayStation 4—codenamed "Orbis"—could be announced at E3, or even as early as May this year.
Speaking to Chilean website El Mercurio Online (via VG247 and CV&G), the Sony executive expressed that while the development of the company's next generation console remains a tightly kept secret, his friends working on the project are getting ready for something really big at E3 in June. "The announcement can take place there or even before, in May," he said.
Given that Sakamoto isn't directly privy to the development of the PlayStation, as he works at a different division from the one developing the console at Sony, his words should be taken as a grain of salt and not as confirmation that the studio will follow up on his predictions.
Beyond that, the whole interview may be nothing more than a case of Chinese telephone. You know, the one where one person tells another person something on the phone and it gets relayed several more times to a dozen other people and the end message is dissimilar from the original.
With that said, there's a good chance that the company will announce the next generation console at E3 as they've given just about every indication that they'll be doing so this year.