Mathematics teaching and learning are inherently complex practices, and reports suggest that American teachers are not as successful at teaching mathematics as the authors might hope. In this article, the authors explore how a seemingly ubiquitous new technology--the personal audio/video player--just might help teachers improve mathematics teaching and learning. This article explores how the video iPod[TM], new on the technological frontier in teacher education, can be utilized to support teachers' learning in and from teaching practice. The authors begin by outlining affordances and limitations of various video-based technologies that have been used in mathematics teacher education over the last two decades. Then, they provide an illustrative case in which video iPods[TM] have been employed in a longitudinal professional development initiative designed to help 5th to 9th grade teachers improve their practices in teaching algebraic thinking to English Language Learners (ELLs). Here, the authors report how teachers use the iPod[TM] and what it enables them to do, and share their preliminary findings that suggest personal audio/video players can foster both greater autonomy in professional learning and greater participation in more rigorous professional development discussions, thereby creating increased opportunities for teacher learning. The authors conclude by looking toward the future, considering new ways of utilizing the technologies and posing questions for continuing research. (Contains 1 figure and 2 notes.)