http://www.wikihow.com/Write-a-Memo contains good information on how to right a memo. It is very similar to the purdue web-site. The only thing that it does not contain is the example of the memo.
Here is our Memo
TO: All ConAgra Employees
FROM: Matthew Everette, Public Relations Manager
DATE: October 15, 2009
SUBJECT: Salmonella Outbreak