During Nokia's Capital Markets Day event, held on December 2nd 2009, a few screenshots showing Symbian^3 were shown off as part of Kai Öistämö's (Nokia EVP, Devices) presentation. While the big Symbian UI rewrite will not happen until Symbian^4, there are still some significant changes in Symbian^3. Read on for further details and commentary at AllAboutSymbian.
These are the first public visuals / screenshots we've seen of Symbian^3 (see note below). Ofcourse theses phones are concept devices - the actual symbian ^ 3 phones wouldn't probably be as awesome.
Also as Rafe Blandford noted:
The presentation referred to the screenshots as from a future UI, rather than Symbian^3, so it is possible than some of the concepts will not appear until Symbian^4 (this applies especially to the last two screenshots).
So we'll have to wait and see what eventually shows up.