PS2 to USB adapter (I have this working on my Windows 7 x64)
PS2 Controller (Obviously)
JoyToKey (Converts game controller buttons to key strokes on your computer)
Wifi Keyboard (Android App)
Verify that your PS2 controller is talking to your computer
Control Panel -> Devices & Printers -> Twin USB Joystick -> (right click) -> Game controller settings -> (depending on what port you've connected the PS2 controller, select the Properties on one of the "Twin USB Joystick"
you should see that the buttons respond. While you are here, I would click on the "ANALOG" button on your PS2 controller and make sure the red light is on.
Map the buttons to keyboard strokes
Open JoyToKey on your computer.
You need to first check these 2 options on JoyToKey under the "Others" tab.
-Use Axes other than X and Y.
-Use POV switches.
If you haven't done so enable ANALOG mode on your PS2 controller.
Go back to the Joysticks tab in JoyToKey, and either select Joystick 1 or Joystick 2 depending on what port you've connected your PS2 controller.
You should map your controllers as shown below.
Button 1 4
Button 2 2
Button 3 1
Button 4 3
Button 5 8
Button 6 6
Button 7 5
Button 8 7
Button 9 Enter
Button 10 F5
Button 11 7, 9
Button 12 0
Enable Wifi Keyboard to run in the background
The trick to doing this is selecting it as the input method, and it stays running in the background. Follow the instructions on Wifi Keyboard by going to a URL in your Internet browser. Should be something like http://192.168.1.2:1111 Then select "Game mode" under Keyboard Mode on the web page. Click on the big area to type in called "Android input".
Open the GTA III app and enjoy.