When Facebook first hit the internet it was like the wild West. An untamed territory with fewer rules. As the team has reigned in the lawless ways and evoked a peacetime, profit machine, rules are being broadcast. But, no one is listening. Take, for example, contests. People are still posting contest in their status updates, asking for inappropriate responses, and announcing winners in the stream. What are the rules now? To review the rules, it is best to look at the official Facebook terms of service in regards to Promotions.
Here is a link.
The basic run down is that you cannot just post a contest with a status post. They must be run on a 3rd party app or canvas page. it must be clearly written that Facebook does endorse your contest. And all rules and regulations must be clearly stated. There are some cool sweepstakes apps and they can be pricey! There is only one that I have found that is truly free. Hooplasoft.com can help in creating completely FREE promotions. Check out this link for the app.
I have heard that Facebook “police” will remove your page if you are violating their terms of service. Why risk it? Do it correctly, get more fans, and everyone is happy!