In addition to all the commercially available tools listed above, ARM also supplies a version of RealView Develoment Suite free for Symbian Platform application development purposes.
Up to date information on the status of Symbian can be found at the Symbian blog.
Nokia maintains a number of tools and SDKs for Symbian development:
The Symbian Foundation is transitioning to a licensing organization. Further information is available at the Symbian Foundation blog.