1. Make sure the project that you have is OK with you changing their software, otherwise what you're doing is illegal.
2. I found a couple of places where this could be done, but one is not free if the files are over 5kb.
DePython is an online service which will do this, but only up to Python 2.5, and costs some money after 5kb.
UnPyc supports 2.6 as well, but some people say it doesn't work. I've never needed to use the tool, so I'm not sure.
Hope it helped!