What kind of bay adapter do I need to buy for a SSD?

^5 +1 what clarkjd and sminlal said. Some of the "retail" versions come with a bay adapter, SATA cable, and maybe a cd-rom disc with a few goodies. You have to check the specifications to make sure.

My ssd did not come with anything so I bought the Silverstone bay adapter:

http://www.newegg.com/Product/Product.aspx?Item=N82E16817997007

Works for me. It came with a plastic bag containing lots of screws in two different sizes.

TIP - Attaching a solid state drive to a drive bay or a bay adapter is a lot easier if you use a magnetic screwdriver.