Symbian is now referred to as Nokia OS and will be supported until 2016. However, due to poor sales of recently released "Symbian" phones Nokia may decide to end support earlier than that.
Or, rather, Nokia renamed "Symbian Anna" and "Symbian Belle" to "Nokia Anna" and "Nokia Belle".
In any case, Nokia did already a year ago say that it is going to gradually phase out Symbian in favour of Windows Phone on their smartphones.
Nokia incorrectly (as many people tried to tell them) assumed that they'd still be able to sell a lot more Symbian phones after that, but the sales have been stagnating ever since Nokia's announcement a year ago.
Accenture, who acquired Nokia's Symbian developers last October, has already started the activities to let some of the people go, because Nokia is no longer paying Accenture for them to work on Symbian, and presumably because Accenture has not found other projects/customer for them, either.
So, yes, Symbian is on the way out as an OS (regardless of whether Nokia's marketeers have deviced to rename it or not), and I would not expect to see too many new models based on that OS.