We created a public wiki:
That everyone is encouraged to participate in. The google code wiki has a huge disadvantage, that only the members of the google code sympy project are allowed to edit it. wiki.sympy.org can be edited by anyone and we hope that it will encourage SymPy users to help improve SymPy documentation and take part in the project.
We plan to move all tutorials and docs in there. Only things, that are relevant to developers, like how to do a release, etc., will stay in the google wiki.