Nokia recently announced their intention to purchase the remaining shares of Symbian and make the Symbian O/S available for free.
As stated in the Reuters piece this was an obvious move by Nokia to head off Google's entrant into the free mobile O/S space; Android.
Device manufacturers, large corporations and even consumers now will have additional choice of mobile O/S because of this move. But is it necessary? Or desired? MySQL was purchased by SUN last year and has seemed to lose momentum. It will be interesting to see how Nokia attempts to invigorate the Symbian O/S.
If you are a mobile application developer wondering which O/S's you should be supporting take note of Symbian with it's European market share and keeping the geographical location of your target markets in mind; act accordingly. Android by Google is already delayed in its release. Remember never bet your business on vaporware! Build your apps for operating systems that are available today. Let your competitors ride the "bleeding" edge. Settle for the leading edge within a conservatively defined market space.