comma seperation in textbox?

Question

hi,
i am sending message to multiple mobile numbers. i am taking one textbox for enter mobileno's for sending a message. if user want to send multiple mobileno's then put comma and write another mobileno.
               i write a one method i.e., sendMessage() in this method i retrive mobileno from textbox. i send message to one mobile number its working but user user enter multiple mobileno's that time number comes one by one to the SendMessage() method from textbox.
how to write this type of code?
please give a solution
thanks