before you do that you are going to want to format it to fat32 so that ps3 will recognize it. this woud be much easier to do while it is in the enclosure....assuming you have the usb cable....also assuming that it is not already formatted fat32. if it is not [http://www.online-tech-tips.com/computer-tips/formatting-external-hard-drive-to-fat-32/|you can follow this guide] is suggest using the swissknife program. as far as teardown [http://www.viddler.com/explore/jpozadzides/videos/130/|i found this video]
Good Luck,
Cody