I recently bought a Ruark R4i and as good as the unit is, there isn't a bluetooth option. However, after a little research, the Layen i-sync popped up. The reviews were good so I ordered it.
It turned out to be just what I wanted. I simply plugged it onto the 30 pin connector, a quick scan via the bluetooth on my phone and it was up and working within 10 seconds, yes, 10 seconds!
A great bit of kit and well worth the money.