  The D0 experiment is facing many exciting challenges providing a computing
environment for its worldwide collaboration. Transparent access to data for
processing and analysis has been enabled through deployment of its SAM system
to collaborating sites and additional functionality will be provided soon with
SAMGrid components. In order to maximize access to global storage,
computational and intellectual resources, and to enable the system to scale to
the large demands soon to be realized, several strategic sites have been
identified as Regional Analysis Centers (RAC's). These sites play an expanded
role within the system. The philosophy and function of these centers is
discussed and details of their composition and operation are outlined. The plan
for future additional centers is also addressed.
