do you want to permanently use the hard drive as an external drive? if so, then yes as rab777hp said just get a drive enclosure to convert it to an external drive
however, if you only need to temporarily access it externally (e.g. you will later re-install it in some computer), there's a more flexible alternative.
get yourself a [http://www.newertech.com/products/usb2_adapt.php|Newertech USB 2.0 Universal Drive Adapter], or similar product from another manufacturer. This will let you attach any ATA or SATA drive, 2.5" or 3.5", hard drive or optical drive - via USB to your computer. it's a very handy adapter to have around when you're swapping or cloning drives. But as I say, this is only for temporary use, it's not meant to replace an external drive enclosure.