At my old school we confiscated the cell phones and they couldn't get them back until the parent came in and got it. Sometimes the kid forgot (if it was an I Pod) and didn't get it back until the end of the year.
Last year when I was subbing, one of my kids was walking down the hall, texting. He was warned. He came into my class and they started working on their writing pieces, or in groups. I snuck over to my computer and checked my email; another teacher had just emailed me that she caught one of her kids texting the one in my class! I sneakily went up to him and said, "Give me the phone, stop texting..." He tried to look innocent, but he handed it over and was amazed that another teacher had relayed this information.