It's a SATA HD, so you can plug it into an open slot on your computer, or plug it into SATA cradle (or external SATA cable).
You'll be able to get unprotected saves off, but not downloaded games or tracks for music games. I think only Capcom really does the protected saves thing, but I'm not really sure.
If you have any music game tracks, you can call Sony and they'll set you up. It's a bit of a hassle, but if you push enough and get connected with the right person, you'll be able to redownload your music purchases.
Any games you downloaded will be able to be downloaded through the PSN Store, should it ever come back up.