Armstrong won the Tour de France each year 1999-2005 and returned this year after a three-year layoff. He is in third place overall with Alberto Contador the leader. Contador and Armstrong both ride for Astana this year.
Armstrong, 37, posted a video on his Livestrong.com Web site announcing the agreement with Radio Shack.
"Radio Shack has agreed to partner with us on this venture," Armstrong said. "The other interesting component is the technology component. Technology is so important in what we do as a cycling team and now as a society. I can't think of a better partner to help us grow the team and remain in the front."