You have to write one… A privacy policy is just a bunch of text
stating what you will do (and will not do) with user information that
you collect or currently posess.
Usually you can just go copy one from an existing web site and modify it
to meet your needs.
Or you can roll your own with these tools:
http://www.oecd.org/document/39/0,2340,en_2649_34255_28863271_1_1_1_1,00
.html
Good luck!
-Brian