Please see the post that came before this for getting your CND pass... This one deals with getting your cell phone.
You have to talk to Frankie on the top patio walkway. You then have to talk to one of the gals dancing on Level 2, forget her name. Actually you might want to talk to her first since it seems to start the cell phone quest. Then, you have to talk to Trey up on level 3 in the lounge. He gives you a tour of the town you must go to the waypoints. Once thats completed, you return to him. Then he will invite you to go up and talk to the DJ. You talk to the DJ, he will give you a cell phone.
It took a bit of time, but was simple. I still not know what use the Phone will be though... But that is how you get it.
Also, you need to get your pass or you will die when you go places.