[Twisted-Python] Installing 2.5 from source on OS X fails...

[Nathan]

My project teammate has a nearly identical MacBook Pro as mine (we're
both running Leopard 10.5.2), but installing from Twisted 2.5.0 from
source (sudo python setup.py install) succeeds on my machine, while on
his machine it complains about a missing Python.h file.  Does anyone
know what package provides that Python.h file?  Is it one of the
packages on the Leopard DVD?

~ Nathan