This is the wiki page for the Linux4nano project. Linux4nano has a fairly active IRC channel, #linux4nano @ irc.freenode.net for questions and comments. Here is the project homepage, and here is a link to the project's mailing list, but these two are rarely updated.
We now have code execution on the 4G Nano! Also, *VERY* primitive Rockbox running on 2G Nano. (as pictured to the right)