finding python modules

[python newbie]

Guys,
Very beginner question.
I'm importing xml.dom.minidom at the top of my file.

I'm trying to figure out where the heck this is. According to Quick Python,
there should be folders on my drive
 (using XP), under c:\python23,   named xml, then underneath: dom, etc.  But
there isn't.

I know that xml.dom.minidom is not built into sys.built_module_names,
cuz I viewed this variable under IDLE.

Could you tell me how Python finds this hierarchy?

  ( the reason for this knowledge is to figure out how to add XML_Objectify
to my path, but I'm trying to do it myself)

Thank you
Steve