I don't think I have ever heard "roster" in the UK, though I would know what it means if I heard it. "Rota" is a nice word for this meaning, I suppose it is related to the Latin rota, which means "wheel". Is this right?

Edit-in: Manuela, a rota is, for example, a list of people that are taking turns doing something... Three of my neighbours have a rota system going to pick up their children from primary school. Each day, a different one does it, and they have a list of who is doing it when.