iPhone - SkyFire browser (Free in the App Store)
Android - Dolphin or Puffin browser (Free in the GooglePlay store)
Windows8 Phone - Flash player is embedded in the browser by Microsoft. (honestly, I don't have a clue how to enable it - I don't have a Windows phone)
The recommendation for all is that you not view in Mobile mode because it will put a load on your processor and drain your battery.