This page is a collection of helpful hints, tips, and links to useful articles about setting up the development environment to work on Melange.
Google App Engine & eclipse (PyDev)
To use the copy of dev_appserver.py that is checked into the SoC svn repository change the Main Module to something like:
${workspace_loc:soc/thirdparty/google_appengine/dev_appserver.py}
This example assumes that trunk/ was checked out and placed in an Eclipse project named soc, so adjust it as needed to point to the dev_appserver.py in your svn working copy and Eclipse project hierarchy.
You will also want to replace the "${project_loc}/src" in the Arguments tab with "${project_loc}/app".
Creating mashups on the Google App Engine using Eclipse, Part 1
Python: Debugging Google App Engine Apps Locally