Q: Where can I learn about programming my Jail broken iOS device? I'd like to do some R&D pushing the boundaries of iOS devices. Is there a how-to guide or private API documentation?
Is there a Stack Exchange site for this?

A: There is a Stack Exchange proposal but it's lacking support:

[...]for iOS developers who require
  help and advice when using
  undocumented iOS APIs. Developers who
  discover private iOS APIs and need a
  place to document them.

http://area51.stackexchange.com/proposals/18154/ios-private-apis
