The first rumors about the Galaxy S III was that it would be introduced at CES in January, but it wasn't. Then the next rumor was that Samsung would drop the next iteration at Mobile World Congress in Barcelona, but they didn't.
The Verge reported that Samsung didn't want another long lag between the phone's announcement and availability, though some speculated that Samsung simply wanted to have an S III event to showcase their new flagship device.
The next rumor of a Galaxy S III event comes from ZD Net Korea, and they seem to think that April is prime time for a Samsung press event. It's a little tough to make heads or tails out of this news item from because, well, it's written in Korean, but I think I've got the basic idea.
Samsung will announce the new S III with availability in time for the summer Olympics in London, which makes sense. The new device will run ICS, have a really big screen, a pretty fast processor and an NFC chip. Oh, and you can bet your last dollar that it will have that TouchWiz thingy too.
As seems to be common when news stories about Samsung product announcements are published, the ZD Net Korea article makes mention of the fact that the iPhone 5 announcement is coming soon. The POS (aw, come on. I'm just kidding!) will likely be unveiled at that June event that Apple has, and Samsung wants their S III announced and available before Apple unleashes the next version of their gimped up, locked down Apple controlled and dominated (another joke) phone on the masses.
Regardless of when it happens, Samsung has said that the S III will be available before summer, and as we are running out of pre-summer months fast. Throw enough darts at the board and eventually you'll hit the bulls-eye. ZD Net Korea might have hit the mark.
Source: ZD Net