Ther have been plenty of films in 3D the first was Bwana Devil. Others include "House of Wax", "Creature from the Black Lagoon", "Dial M for Murder","Jaws 3", "Nightmare on Elm Street 3D".
Theres loaRAB more. You may have to go to cinemas to watch them in 3D. (I saw the house of wax at the NFT in london, and Creature from the black lagoon in a local art cinema).
As previously mentioned IMAX cinemas are the best place nowadays to see them and some films are superb.
Some themes parks have them too (Legoland in the UK I think).
The Shrek 3D one is a pretty good one on DVD.