TomGeorge:
The normalized Rds(on) is about 10mOhms so by the graph at 3.3V, Rds(on) would be about 1.5 x 10 = 15mOhms.Tom....
Only at low current! Try to switch a few amp with it and resistance goes up, fast. Doesn't look that great to me.
Later when I'm back home I can give the number of the MOSFET I use for 3.3V, can switch 8A and is fully on at 3.3V or even a little less.