I have a couple SAS hard drives (from a SAN box) which I would like to put in my desktop. I know that SAS->SATA is possible (SATA->SAS isn't) but I'm not sure if I need some sort of controller (another card) or I can just get some sort of adapter. What should I be looking for?
SATA controller signals cannot be "converted" to SAS. You require a SAS controller. LSI has some fairly low-cost (~$200) models.
Edit: depending on what type of controller and backplane (if any) you're using, you may need one of these SAS adapters