Yesterday I found an old disk full of games, and on it was GTAIII (for PC). The keyboard controls were ridiculous, so I looked up a way to use the Sixaxis on a computer, and it works. If you dont care, dont post.
NOTE: Various websites say that the drivers required for the Sixaxis can mess up your computer's ability to detect a Zune. So, for the 7 people in the world that own a Zune, don't risk doing this!
I take no credit for the following information, only that I re-wrote them to make them a little easier to understand. I accept no responsibility for what happens when you perform the following steps.
1) Unplug (or use the main power switch) your PS3 so the controller wont be picked up by the PS3. The controller wont work with the PC if it has been assigned to a PS3.
2) Download this file, you can save it anywhere on your computer's HDD >
File Details-SIXAXIS-driver-for-PC-PlayStation-3 -
3) Extract/Unpack the file, doesn't matter where you put it. (You can delete the ZIP file if you want, but keep it just incase)
4) Install the libusb-win32... file from the unzipped folder.
5) Plug the Sixaxis into the computer using the USB charging cable. (The one you get with the PS3)
6) Run ps3sixaxis_en.exe Once.
7) Press the PS button.
To test if it works, go into the control panel and open the game controllers folder. (Or whatever the folder is called as per your version of Windows) If you can move the little cross on the screen, the controller works. If it doesnt work, follow these next steps.
You only need to do this if the controller isn't working yet
8)Move the ps3sixaxis_en file into MyComputer > [Your local disk drive] > Windows > System32
9) Then go into command prompt (Run > CMD)
10) Type ps3sixaxis_en and then just leave the command prompt.
11) Re-test the controller in the control panel.
If it works, then great.
If it doesn't, you either did a step wrong or your controller is connecting to your PS3, see step 1.
I tested this in Windows Vista so it does work with the most current OS. I don't know about Linux but I am confident about it working on modern versions of Windows.
I have being playing GTAIII on my computer using the regular PS2 setup, bit of nostalgia going on here.