Python: saving NEW excel with a splitted column

Python: saving NEW excel with a splitted column

alright say I have an excel file that looks like this:
http://oi44.tinypic.com/52e8fp.jpg
the fourth column (D) has several values in it. I want to use Python to
create a new excel file, only with that column split into several.
basically I want this: http://oi41.tinypic.com/2a7hlzb.jpg
I'm just not sure how I would go about creating "new" columns? I'll have
to split column D, and then what? is there a way I could make lists with
every value belonging to a different column (i.e. john, smith, 23,
fireman, purple, cat) and then write those lists as a new excel file?
I'm using xlrd and xlwt to do this.
thanks!