Looking for an easy and inexpensive way to get one more SATA connector in my computer, I came across this PCIe SATA card. It's got no electronics on it, just PCB traces to connect some of the PCIe bits to its female SATA connector. Every other PCIe SATA adapter that I've seen has some electronics on it ... but they also support more than one SATA device.
I'm upgrading my SSD from an Intel SATA II 320 120GB - which has worked very well for me - to a Samsung SATA III 840 EVO 250GB. My computer doesn't have any native SATA III hookups, but I do have several PCIe 2.0 slots that are open and ready to be used.