UPDATE (2019-04-22) - It sounds like you want to use uncompyle6 nowadays rather than the answers I had mentioned originally.
This sounds like it works: http://code.google.com/p/unpyc/
Issue 8 says it supports 2.7: http://code.google.com/p/unpyc/updates/list
UPDATE (2013-09-03) - As noted in the comments and in other answers, you should look at https://github.com/wibiti/uncompyle2 or https://github.com/gstarnberger/uncompyle instead of unpyc.