If it's in salt water there will be a lot of sealife, the most pictures I have seen the plane i covered with shell fish and other living things. The corrosion will also eat its part of the plane. Anything made from fabric will be gone in a few months.
In fresh water fabric will not be destroyed. The plane will be covered in dirt that the currents bring, mostly sediment. There was a nice documentary of the b-29 that is on the bottom of the lake Mead behind Hoover dam, even the silk parachute was intact.
Half way down the page of the following link and you will find a nice photo of the b-29 cockpit.
http://airplanes-underwater.blogspot.com/2006_01_01_archive.html
And here is a Brewster that has been in a fresh water lake for 50 years:
http://www.virtualpilots.fi/en/feature/artikkelit/bw372-esitelma/bw372_3.jpg
Michael