If I had to write a paper for...a communications class, a business class, a sociology class, a public speaking class, or maybe an English class!...and the assignment was about the pros and cons of cell phones, this is what I'd use:
Okay then: I've found a good working thesis and also made the idea into my title. Then I have several options for topic sentences that I can extract and resubmit in paragraphs to build my paper. And note how I've used a classic role model from society/archetype: the "Secret Agent" image, even if it is a comedy TV show.
The topic sentence themes are
(1) best sales opportunities that can be found with a cell phone,
(2) navigation assistance while driving,
(3) weather alerts,
(4) finding out who's where and what's hot for fun with friends,
(5) health risk alerts: keeping a phone too close to the body (and head),
(6) people can't do simple math skills without a cell phone/calculator!,
(7) lack of social etiquette and manners while using a cell phone.
(And I didn't even include the dangers of texting and driving. Nor did I mention the issue of cell phones in school. For that matter, what do you think of my idea of assigning guilty-in-class-time cell phone users some extra work?)
I would suggest doing BOTH pro/con sides in a paper like this because it shows better research as well.
Now, for some research material, I would use...and there's certainly more available in other places!