Just got my kids ipod touches and an iphone. Do they each need their own account?

Do I need to set them each up their own account? They are 9, 10, and 11

They don't NEED an account each, however if they all sync to the same iTunes account then all music, preferences, contacts and pictures will be shared across all the devices.

this could mean that they have access to things you don't want them to… Alternatively it could mean you can keep track of what they are doing with the phones

setting up an account for each of them will solve this problem.

Don't let the kids take them to school either… Not a good idea