Here is the link to our fundraising page on our website. It you go to the section labeled "patron drive," there are copies of our letters, sample speeches and other hints.
http://www.penfieldrobotics.com/team/fundraising.php
We also have a trifold describing our team and FIRST that the students take with them. Most of our initial contacts are done face to face or by appointment so the letter is a follow-up rather than an initial contact.
Good Luck!