Get on the (Symbian) boat
As far as I have been able to read on the Web, Symbian has no reputation of a developper-friendly operating system. The good news is that it might change in the future. Nokia, who has recently bought it, is making it opensource, and has just opened the repository and the community website. It seems to use Mercurial, MediaWiki, and provide documentation, and that would be a good start to build a community of developers, according to this. The rest is all about communication and community management (not the least, though).
I'm not a developer (yet), but I can say that getting some information from Nokia developers website proved to be difficult to me, and not pushing you to try to code your stuff for their platform. I hope all this is the sign of a change for something better. I especially hope that soon, people will be able to update a modified version of their OS on their mobile device.
