How to test if a module exists?

[Roy Smith]

In article <mailman.710.1289095058.2218.python-list at python.org>,
 Jon Dufresne <jon.dufresne at gmail.com> wrote:

> I went ahead and implemented this and it now works. I even uncovered a
> bug I wasn't previously seeing because now the program was failing
> early! :)

Excellent.  Fail early and often, that's what I say.