Well.....you can just plug the fans into the power supply directly. You may have to buy a power adapter depending on what connections your fans have. If they are 3 pin powered fans you need one of these http://www.newegg.com/Product/Product.aspx?Item=N82E16812189119
If they are 4 pin powered fans then you can just plug them into the power supply and don't need to buy anything.