Just a sidenote, the (salt or dirty) water messes up the battery first (short circuits it), then the buttons where the dirt prevents contact. Also the camera is not waterproof? Speakers and mic are also very sensitive to debris and water.

@vmayur_23: Let the phone dry out in the rice, the few days should be enough. If you can find something dryer, use that? There are many things that can go wrong with water, and the phone needs maybe only one thing malfunctioning to not function. Also, something can be broke internally - the water caused something to malfunction and that malfunction broke something else.
The phone is a very complex device, it usually is cheaper to replace it completely than diagnose and replace parts of it. Battery, SIM card and memory card are the only salvageable parts, maybe you can keep the external shell as replace parts for the new phone.

http://ezinearticles.com/?10-Simple-...Wet!&id=455630

http://www.helium.com/items/631539-h...er-it-gets-wet