The XenoServer project will build a public infrastructure for wide-area distributed computing. We envisage a world in which XenoServer execution platforms will be scattered across the globe and available for any member of the public to submit code for execution. Crucially, the code’s sponsor will be billed for all the resources used or reserved during its execution. This will encourage load balancing, limit congestion, and make the platform self-financing. Such a global infrastructure is essential to address the fundamental problem of communication latency. By enabling principals to run programs at points throughout the network they can ensure that their code executes close to the entities with which it interacts. As well as reducing latency this can be used to avoid network bottlenecks, to reduce long-haul network charges and to provide a network presence for transiently-connected mobile devices. This project will build and deploy a global XenoServer test-bed and make it available to authenticated external users; initially members of the scientific community and ultimately of the general public. In this environment accurate resource accounting and pricing is critical – whether in an actual currency or one that is fictitious. As with our existing work on OS resource management, pricing provides the feedback necessary for applications that can adapt, and prevents over-use by applications that cannot.