We present an experimental scheme to generate a class of entangled atomic W states useful for perfect teleportation and superdense coding. It employs three two-level (Rydberg) atoms crossing two nonresonant cavities in such a way that the first and second (the second and third) atoms are entangled via atomic collision in the first (second) cavity. The experimental realization with current technology is discussed. © 2008 IOP Publishing Ltd.