Create a separate vlan for VOIP using the same data port on the switch

Hi, i am new to Vlan but i want to know how to create a separate vlan for my VOIP phones. They are connected now to the same port on the switch where the computers are. The phones are like a swith, the connection of the wall comes into the phone and from the phone to the computer. But i want to separate the traffic using a vlan. Let me Know!!
thanks