16V DOHC VVT-i engine means that it is a dual overhead camshaft engine. This type of engine basically has two camshafts assembled on each engine head. 16V means that the engine has got 16 valves and VVT means that the engine has variable valve timing.
Millicentmach is correct. Also, 16 valves probably means 4 cylinders with 4 valves per cylinder, since each camshaft will usually run 2 valves per cylinder-1 inlet and 1 exhaust. The i probably means its fuel injected, but I'm not positive about that.