We're hearing from people familiar with the matter that Samsung — which had originally planned to announce its 2012 flagship Galaxy S III phone at Mobile World Congress in Barcelona late next month — has now decided to delay the news. It's unclear when or where the new announcement will be, but we're told that it'll still be out there "before summer." Though MWC seems like a logical choice for the GSIII's unveiling (the GSII was announced there last year), the speculation is that Samsung was uncomfortable with another long lag between the global launch and US availability. The US is a key market for Samsung's mobile business, of course — particularly when the company is successful in getting most or all national carriers to pick it up.
While we don't know what exactly Samsung will be announcing at MWC in the GSIII's place, we understand the company will have "interesting stuff" — perhaps a Galaxy Tab refresh, especially since the 10.1 is getting long in the tooth and we're due for a round of quad-core updates in 2012. A new Windows Phone portfolio is another possibility; there have been rumors that Microsoft will make an announcement at the show, and Samsung is about as strong a Windows Phone partner as Microsoft has outside of Nokia. We'll be following this story closely as it develops.
Update: German blog BestBoyZ, which has been accurate in the past, is reporting the same thing.