As others have already said, it goes on a case by case basis, in some instances you may need to use additional SATA drivers (given on a floppy disk) for the OS to be able to even see it.... This is only when your installing an OS onto it on a new PC. From experiecne I've installed the same OS (WinXP SP2) on over 20-ish machines (new builds) with different hard drive and motherboard combinations everytime, never once have i needed to sue the additional drivers, but thats not saying you don't need to. I think i just get lucky everytime.
If your simply adding an extra SATA drive to your existing fully working fully installed PC (as a second or slave drive) then it is literally plug and play, plug the SATA cables in give it some power and away you go. Some BIOS's disable SATA ports so you might have to go in and physically enable them, but thats no biggy
dragon2309