There is a link for a free copy of the DSST study guide that includes the ethics exam (I printed it this week there are more than what is listed), look under the link for exam resources for newbies, posted by Steve Webmaster from oldrustpipe. I copied it here but you should look through that post a lot of useful info in there.
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A useful link as posted by Old Rusty Pipe:
http://www.petersons.com/pdf/free/DSST.pdf
Check it out. It covers:
-Principles of Supervision
-Intro to Business
-Human Resources Management
-Organizational Behavior