In case you didn’t know, Symbian is the primary OS on most Nokia phones (with the exception of the newer Maemo-based ones) and is the most popular OS worldwide, with over 330 million devices sold in 2009 alone. In June 2008, Nokia bought Symbian and created the Symbian Foundation which is comprised of Nokia, LG, Motorola, NTT Docomo, Samsung, Sony Ericsson, Vodafone, AT&T, and Texas Instruments. Nokia has been the primary developer of Symbian, but they plan to reduce their part to less than 50% by the second half of 2011.
By making the OS open source, they’re hoping it can compete further with the iPhone and Android, which is also open source. The source code should be available later today on the Symbian Foundation’s website. They hope this move will also help increase the production of 3rd party apps and improve security of the OS.
Source: GSMArena