I used the windows installer for the latest version of psyco, which is labeled as compatible with 2.5, but it gives the following error:
ImportError: DLL load failed: The specified module could not be found. (check that the compiled extension 'C:\Python26\lib\site- packages\psyco\_psyco.pyd' is for the correct Python version; this is Python 2.6) -- http://mail.python.org/mailman/listinfo/python-list