I have been once in a submarine and I have to say it is great! Especially if you are near the window. Submarines are usually for military purposes instead of tourist, but I really liked the ride. Have you ever been on one? How was it?
Also, here is a useful source of information about submarines.
Edited: Smudge on 11th Jan, 2005 - 3:10am
Well, I've been in a submarine before, just sadly not a working one. They have a submarine from World War II up in Hamburg, which is open to the public. I must say, it was pretty cramped and I certainly wouldn't want to be underwater in that thing.
Every August they hold an event in England called 'Navy Days'. it is always down south, and alternates between Portsmouth and Plymouth, (Royal Navy bases)
My Son wants to go into the Navy, so we go to Navy Days every year. Each year, you can go on a submarine, war ships, have a ride on a 'rib raider', watch the military tattoo,etc everything to do with the Navy is there, including helicopters and planes.
When I have been on the submarines,it feels very cramped, on not for the claustrophobic, and very hot!
I certainly couldn't spend longer than an hour on!