Corn snakes are among the best snakes for beginners and advanced reptile keepers alike. There is so much variety possible and so many beautiful colors and pattern in this active, calm, easy to care for snake. I highly recommend beginning by reading a good book on their care and requirements to get the basics on their requirements before purchasing a snake. This book: 'The Corn Snake Manual' by Bill and Kathy Love is excellent with good advice, great pictures and lots of detail on all aspects of corn snake care.
These snakes live about 15 years and reach an adult size of about 5ft. They love to climb and can live in aquariums, rubbermaids or custom enclosures. Whatever cage you choose, it need to be very secure as they are amazing escape artists. They need a temperature range of room temperature with a hotter area about 85F. Keeping hides on both the warm and cool sides of the tank is helpful to give the snake a safe, comfortable choice in hiding place.
Useful caresheets can be found here: http://www.wnyherp.org/care-sheets/snakes/corn-snake.php and here: http://www.reptilescanada.com/forums/showthread.php?t=18414