Make sure you choose a USB-C or micro-USB connector depending on what your phone uses. Simply connect the USB-OTG dongle to your Android phone, then connect the USB game controller to that. Games with controller support should detect the device, and you'll be ready to play. That's all you need.
Yes, Sixaxis Controller lets you use your wireless PS3 controllers with your Android phone or tablet, making your new Galaxy Tab or Xoom an emulation paradise. You can download the app in the Android Market, but be sure to check if your device is compatible first by using the compatibility checker app.
For games like Beyond Two Souls, Until Dawn, and Heavy Rain, having the DualShock 4 on PS4 is a must. If anyone has in the previous months have gotten these two titles on PS Plus, one thing you must know is that you absolutely must have a DualShock 4 controller, and not any other wired controller just to play the game.
Apple technically tells you if a game supports controllers or not. If you're on the game's landing page, look for the Controller icon under the Get link.
Connect your PS3 controller to your computer with a USB cable and wait for the Bluetooth address to come up. Once it's paired with your computer, get your iOS device's Bluetooth address by heading into Settings > About > Bluetooth. Now your iOS device should be linked to your PS3 controller.