Simon,
Normally a two pole switch will work but you might want to consider double throw switches so that the inputs are switched into 10,000 ohm resistors when they are off line. The resistors will help in charging the output capacitors in each source device you have connected. Without resistors you might experience a slight pop when switching between inputs. Take a look at the MCM catalog
http://www.mcmelectronics.com/ A #50-5725 Six input Stereo Line Level Source Selector is likely what you are looking for at $57.70. Less expensive but with top mounted switch is #50-5180 at $16.50. VIDEO SELECTOR 6-INPUT 2-OUT L/R AUDIO S-VIDEO #50-7780 will give you added ability to switch video as well at $37.89.