From eServer Magazine, a story on Grid Computing and what IBM is doing:
Rather than countless PCs sharing tasks, imagine a large cluster of mainframes and other servers acting as a single integrated computing system that can be accessed by home- or business-based PCs. Beyond simply sharing files and information, users can access an extensive grid of high-end enterprise computers via the Internet, using idle compute cycles to crunch massive amounts of data. Certified users could access super-computing resources, computing clusters, data-storage systems, data sources and even network with other grid users. Taking it even further, users could create entire virtual organizations with complex business processes running remotely. The only costs involved are likely to be those charged to lease grid resources.