I'm new to python programming, and want to try to edit scripts in IDLE instead of the OSX command line. However, when I try to start it, it gives me the error "Idle Subprocess didn't make a connection. Either Idle can't start a subprocess or personal firewall software is blocking the connection." I don't have a firewall configured, so what could the problem be?
You can try running IDLE with the "-n" option.  From the IDLE help:

Running without a subprocess:

    If IDLE is started with the -n command line switch it will run in a
    single process and will not create the subprocess which runs the RPC
    Python execution server.  This can be useful if Python cannot create
    the subprocess or the RPC socket interface on your platform.  However,
    in this mode user code is not isolated from IDLE itself.  Also, the
    environment is not restarted when Run/Run Module (F5) is selected.  If
    your code has been modified, you must reload() the affected modules and
    re-import any specific items (e.g. from foo import baz) if the changes
    are to take effect.  For these reasons, it is preferable to run IDLE
    with the default subprocess if at all possible.
No IDLE Subprocess connection