hckycoz,
I'm sorry to hear about your problem getting paid. There is no excuse for that. There are a couple of things that you can do (sorry but as an attorney I can't recommend busting his kneecaps with a baseball bat - its considered unethical). Several folks suggested contacting the Department of Labor which is a very good suggestion. They have considerable clout in these matters and most employers are terrified of them. However, once you contact them it is no longer in your hands and there isn't enough money to pay all the employees they have stiffed then you will just get your share. Accordingly, the better approach is to tell you employer that you are going to contact the Department of Labor if you do not receive your full pay within X days. That gives them the opportunity to pay you to make you go away before they end up going belly up trying to pay anyone else that they may owe. However, if you go that route you had better have all of your i's dotted and t's crossed as government agencies are unbelievably nitpicky about such things.
Another option is to contact an attorney to send a letter demanding your pay and threatening to invoke any penalties or other remedies available under the applicable state's law. For example, if you were to get fired by these guys Missouri requires that they pay you immediately and if they fail to even after you have sent a written demand that they do so you are deemed to continue earning full pay up to a maximum of 60 (or is it 90) days which you can then sue them for. Sorry but it only applies in the case where the employer terminates you not when you quit.
Once again, I feel for you as there is no excuse for an employer not paying its employees.