Creating an Array from a Multi-line string (Help appreciated)

Hiya, ( first time poster, long time user ;o) ) I am creating an interface page with a multi line text box which will recieve a list of phone numbers on individual lines, so: 12345 12345 12345 and so on... I need to carry out an operation on each of these numbers (add them to a mysql db, but thats not important). Is it possible to recieve this text box in my php script and reference each line? Ideally put it into an array and reference by $number['0'] $number['1'] and so on, so i can have a 'for' loop going? Really need some help on this, much appeciated guys, thanks in advance.