[Tutor] Hot Folders?

[Scott Ralph]

Hello,
I'd like to create a hot folder program in Python..  I'm still in the
learning stage so any help would be great.  Basically I would have a
folder on my server that if and when a file hits it it will do
something..
My problem is I'm not sure were to start.  How can I code in my script a

sort of watcher routine that will monitor this folder?  Also how can I
check if the file is actually done coping into the folder?
Thanks All
Scott