Type
The PlayStation 3 is compatible with nearly any SATA notebook (laptop) hard drive. Even if you are not sure exactly what that is, your computer retailer will help you pick out the correct one.
Speed
The hard drive can be 5400 RPM or 7200 RPM. The more revolutions per minute, the faster the hard drive performs, which can lead to shorter load times and quicker saves.
Size
The SATA drive must be only 2 1/2 inches as it has to fit into the console's 2 1/2-inch drive tray.
Storage Capacity
Because you're already going through the trouble of upgrading, you might as well make it big. Choose at least a 120GB hard drive or go as high as 250GB.
Installation
You can install it yourself, but remember that by doing so, it voids any warranty you might have on your system. If you doubt your ability, seek professional assistance.