You can load a module dynamically like so:

{{{
#!python
__import__("os")
}}}

If you do that, though, "os" isn't bound to anything.

{{{
#!python
>>> __import__("os")
<module 'os' from '/usr/lib/python2.3/os.pyc'>
>>> os
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
NameError: name 'os' is not defined
>>>
}}}

Once you have the module, you probably want to find classes and functions and data inside of it.

Use {{{getattr}}}:

{{{
#!python
>>> m=__import__("mine")
>>> m
<module 'mine' from 'mine.pyc'>
>>> getattr(m, "eggs")
4654
>>> getattr(m, "ham")
'Monty Python'
}}}