Also see Walmart: The High Cost of Low Price, a documentary where they show former Walmart managers describing how they are specifically trained in how to cheat their employees out of over-time pay, and to tell them how to apply for government assistance like foodstamps and medicaid to help prevent the need for Walmart to provide either decent pay or benefits, thus subsidizing Walmart's profits. The DVD is only $12.95:
http://www.walmartmovie.com/
You can also keep a running tally of all the lawsuits, labor disputes, and general mayhem that Walmart is involved in at:
http://walmartwatch.com/