http://content.techrepublic.com.com/2346-10877_11-41891-1.html
Option 1:
First of all DON'T DO THIS IF YOU'RE NOT SURE WHAT YOU'RE DOING. The PS3 is an expensive system to mess with for this. The pictures are good, even great, but make sure you are paying attention.
You'll mount your drive inside your computer like a standard internal drive. You can get a converter from most local computer shops for the connector if you need to.
The drivers for recognizing the drive are available on DriverGuide's website.
Option 2:
Buy or download PSLinux3 or PS3Linux. Both include the PC-Out tool which will let you read your BD and HD drives off a computer as an external removable drive, via USB or SATA. You'll still need to crack the shell to install the cables, but if you buy the boxed software it will include the adaptors in the box and the windows/mac/Linux software/driver CD. You'll cut a little hole in the back of the case for the wires to pass through.
You're getting into the realm of advanced system mods with these though. Despite its shortcomings, the PS3 is probably the most advanced computer you can get your hands on at the moment. Moving things around and swapping cables and adaptors takes time, care and knowledge so you don't fry both systems. If it's to much you can always use a popular mod-site and send your system in to be converted (average US$50) or ask around the local game shops to find someone who can do it for you.