According to a report on emol.com (and picked up by CVG), the Playstation 4 could be revealed by Sony as early as May this year, before the next E3 event.
Speaking during CES last week, Sony VP Hiroshi Sakamoto revealed to emol.com that: "our friends at Sony PlayStation are getting ready. I can only say that we are focused on the E3 gaming event, scheduled for June. Announcement may be in that minute or even earlier in May."
When asked whether it was to be a big announcement or something additional he replied: "Probably the first, in that time we expect to deliver great news, but we must wait until May at least."
Announcements for the next generation of consoles from both Sony and Microsoft are expected this year, and with Nintendo already bringing the Wii U to market, and with some major reveals at this year's CES, it's looking increasingly likely that this year's E3 will take on increasing significance for the major platform holders.