This tiny script allows obtaining a file with your public IP. 
My main purpose was put the script in my Dropbox and keep it running 
in my home server to have a "safe alternative" if my dyndns account failed.

You can adjust the interval between IP updates easily modifying time in:
time.sleep(3600)

Just put seconds you want.
setup.py file allows to use py2exe to generate a Windows executable file.