Here is a nice easy guide to show you how to switch out your HDD from your stock Sony PS3 into a mega big HDD. If your like me and you bought a launch PS3 this is very useful and will let you build up your DLC, videos, music and pictures. It seems to be an easy install so step on up and grab a large HDD of your liking and start the upgrading.

1. Buy HDD of course, lol
2. Back up all of you PS3 data onto a flash drive or external HDD for easy recovery. Go to “System>Backup>create backup”. The process could take up to an hour. I would recommend deleting anything unimportant, to speed up the process. Using the backup ensures that you won’t have to re-download or reinstall anything.
3. Shut down and disconnect PS3

4. Locate HDD slot on the PS3. It is denoted by a big label (HDD)
5. Use a flathead screwdriver to remove the plastic cover. Don’t press hard, it comes off easily.
6. Using a philips head screwdriver, remove the blue screw
7. There should be a thin metal U-shaped handle. Fold it towards you, slide the HDD enclosure to the right and pull it out of the PS3.
8. The enclosure secures the HDD via 4 screws, two on either side. remove the screws and slide out the HDD.
9. Slide in the new HDD, chip-side down, into the enclosure. Put the 4 screws back on.
10. Slide enclosure back into PS3 and snap into place to the left.
11. put blue screw back on. Put on the plastic cover too, silly.
12. Power up the PS3. It will ask to format the HDD. It should take a few minutes.
13. Once formatted, go to system>backup>recover from backup. Make sure your external hdd/flashdrive is hooked up. The backup will have a 12-digit name, mostly numbers. The recovery will take as long as the backup took.
14. Enjoy new HDD in your PS3.

Thanks to nostars for the how-to-guide!