Short Put
A Bullish options strategy that involves selling short or "writing" a put option. When the stock rises above the strike price of the short put by expiration, the put options expire worthless and entire premium from its sale is earned.
The seller of the short put (gets the premium) is betting the stock price will be above the strike price on expiration so he can keep the premium.
The buyer of the short put (pays the premium) bets the stock price will be below the strike price on expiration so he can sell the shares at the strike price, i.e., above the (then) market price.
See Also
http://www.wikinvest.com/wiki/Options_-_Short_Put?action=edit