Can more than one iOS have the same Apple ID?

Right now I have the Ipod Touch 5th Gen and I'm thinking about getting a Iphone 4 or 4s. Do I have to make a new apple ID or can they both have the same account on it? And also, how would Imessage work if they both could have the same apple ID?

They can have the same ID. Imessage would go to both of them.