Firstly, this app is for ANDROID PHONES ONLY.
It won't work on anything else. The app can be found here. There is also a checker that you can download and see if your phone is suitable. That can be found here.
You could also visit the Dancing Pixel Studios site here.
Now that that is cleared up, you need to have some pre-requisites before this app will work.
1. A Sixaxis PS3 controller. It isn't recommended to use any other pad as they can produce technical issues. A USB controller WILL NOT WORK so don't ask.
2. Your phone needs ROOT. If you don't know what this is I suggest you do some reading at XDA Developers of Cyanogenmod.
3. A PS3 sixaxis charging cable - Due to the way pairing is done with the controllers, you need to manually pair your controller with the PC utility 'SixaxisPairTool' (available on the website) and a mini-USB cable. Android 3.1+ users can also pair directly on their devices via USB.
I personally use an LG Optimus 2X with Cyanogenmod 7 and this app works flawlessly.
There are numerous guides on youtube how to create the key maps so I wont bore you with details.
Anyway, onto key mappings.
You can download my touch profiles here.
These are for:
Brothers in Arms 2 (Gameloft Freemium version)
9mm (not working 100% corectly)
Frontline Commando
GTA 3
Modern Combat 3
Nova 2
Simply extract the archive to your SDcard into \data\com.dancingpixelstudios.sixaxiscontroller\profiles
These are designed for the LG Optimus 2X so anyone who uses tablets of phones with larger screens are going to have to tweak these to get them to work properly.
If you have any other questions, please ask!
