The Nation has an interesting article about WalMart's union busting tactics.
Staying union free is a full-time commitment. Unless union prevention is a goal equal to other objectives within an organization, the goal will usually not be attained. The commitment to stay union free must exist at all levels of management–from the Chairperson of the "Board" down to the front-line manager. Therefore, no one in management is immune to carrying his or her "own weight" in the union prevention effort. The entire management staff should fully comprehend and appreciate exactly what is expected of their individual efforts to meet the union free objective…. Unless each member of management is willing to spend the necessary time, effort, energy, and money, it will not be accomplished. The time involved is…365 days per year….
I'm not a big fan of unions, but employees certainly have the right to attempt to form one. This should be a fun battle to watch over the coming years. It's stuff like this that will eventually topple WalMart from the top of the Fortune 500.