RF superconductivity has become an important technology for accelerators at the energy and luminosity frontiers as well as at the cutting edge of nuclear physics and basic materials science. Nearly one kilometer of superconducting cavities have been installed in accelerators to provide more than 5 gigavolts of acceleration. Superconducting cavities support beam currents above one ampere, and deliver up to 380 kW of beam power. Steady advances in science and technology are responsible for spectacular increases in performance since the large installations of CEBAF (Jefferson Lab) and LEP-II (CERN) during the 1990's. The gradient of niobium cavities has more than tripled over the last decade, spurring new accelerators. The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory switched to superconducting technology in 2000. The X-ray Free Electron Laser at DESY will provide angstrom-wavelength beams of unprecedented brilliance. Recently an International Technology Recommendation Panel selected the superconducting option for the International Linear Collider. The 500 GeV collider will require 20,000 superconducting cavities, each about one meter long, operating at 2 K. Energy Recovery Linac (ERL) studies are flowering for a variety of applications: ultra-fast, high brilliance light sources as well as electron beams for cooling or colliding with ions in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Lab. Designs for the nuclear Rare Isotope Accelerator (RIA) demand high performance cavities. With many years of operating experience at major accelerators demonstrating a robust technology, SRF is ready to launch major initiatives.