Just let it dry.
Seriously, trust me on this =P. One of my Nokias fell in Ice Cold Water during the winter, and it worked fine. And I had another experience where my 4 year old bro was running around with my mum's Nokia, he decided to throw it in the toilet. I washed it with water, let it dry for awhile, and it works like a charm.
Give it a day or two, leave it in an area where the water can dry properly. If it the water dries and it still doesn't work, take it to a repair shop.