Here are a few examples of Public Records request letters.
Informal letter
Non-threatening, most effective when used with small agencies
Neutral letter
Neither harsh nor friendly, here’s an example of a standard request
More resources:
Letter generator from The Reporters Committee for Freedom of the Press
http://www.rcfp.org/foialetter/index.php
Letter generator from the Student Press Law Center
http://www.splc.org/foiletter.asp