Today's high-end cell phones have the computing power of a mid-1990s personal computer (PC)--while consuming only one one-hundredth of the energy. Even the simplest, voice-only phones have more complex and powerful chips than the 1969 on-board computer that landed a spaceship on the moon. In the United States, it is almost universally acknowledged that computers are essential for 21st-century students. To most educators "computer" means a PC, a laptop, or, in some instances, a personal digital assistant (PDA); cell phones, on the other hand, are more often regarded as bothersome distractions to the learning process. The cell phone--generally called a mobile phone outside of the United States--has proved so useful elsewhere that there are 1.5 billion around the world, with half a billion new ones sold every year. Cell phones are not just communications devices sparking new modalities of interaction between people. Like all communication and computing devices, cell phones can be used to learn. In this article, the author contends that students can learn "anything" with a cell phone, if educators design it right. Cell phones complement the short-burst, casual, multitasking style of today's "Digital Native" learners. Using cell phones as learning devices, whether in or out of school, requires a good deal of rethinking and flexibility on the part of educators.