CELL is a heterogeneous chip multiprocessor consisting of a 64-bit Power core, augmented with 8 specialized co-processors based on a novel single-instruction multiple-data (SIMD) architecture called SPU (Synergistic Processor Unit), for data intensive processing as is found in cryptography, media and scientific applications. The system is integrated by a coherent on-chip bus.You can read the article here
IBM about the Cell processor architecture

IBM posted an article on its website about the Cell processor architecture, which will be used in Sony's PlayStation 3 console.