There is now an IDL language mapping for python. Download the specification here attachment:01-02-66.pdf
Current implementations of the specification (lets hope this list gets longer!):
[http://www.fnorb.org FnOrb], development seems to have stopped here
[http://orbit-python.sault.org Orbit Python] python ORB with no need for an IDL compiler
Other CORBA specs available from [http://www.omg.org/technology/documents/spec_catalog.htm the omg web site].