Cell phones are now widespread in many countries including Japan where we teach, and are particularly popular among university students. Although they can be a distraction in the classroom, functions such as Internet access and e-mail capability have transformed them into sophisticated communication tools. But are they also potentially useful in language learning? While task-based approaches (Nunan, 1989) adapted to desktop e-mail are now a growing area of research in CALL (Greenfield, 2003; Gonzalez-Lloret, 2003), cell phones have yet to receive much attention. This paper reports on a classroom research project aimed at evaluating the use of mobile phones as tools for classroom learning. Freshman university students in intact EFL classes (2 elementary classes, 2 lower intermediate) were first surveyed regarding their cell phone use and pre-tested to assess their knowledge of certain target learning structures. Following this they were subdivided into three groups: (a) using cell phone text messages, (b) using computer e-mail, and (c) speaking. The learners were paired, trained with warm-up tasks, and given two further sets of tasks to complete (one in class and the other at home). The target vocabulary appeared in the initial narrative task. All messages sent while doing the tasks were saved for analysis. The speaking task pairs were recorded and samples were transcribed for comparison. Finally learners took a post-test the following week to assess short-term learning gains. This project drew attention to a number of potential advantages of mobile phones as well as highlighting some limitations, but overall suggested that mobile phones represent a language learning resource worthy of further investigation.