From the NASA press release:
NASA will provide online updates at:
http://www.nasa.gov/shuttle
A webcast May 10 at noon will start the in-depth online coverage of the mission. Host Damon Talley of NASA's Digital Learning Network and correspondent Rebecca Sprague will preview the mission and examine the remarkable history and discoveries the Hubble observatory has made. Astrophysicist Mario Livio of the Hubble Space Telescope Science Institute will discuss the telescope's impact beyond the scientific community.
A blog will provide launch countdown updates beginning at 8:30 a.m. May 11. Originating from the Launch Control Center at NASA's Kennedy Space Center, the blog is the definitive Internet source for information leading up to launch.
During the STS-125 mission, visitors to NASA's shuttle Web site can read about the astronauts' progress and watch their five spacewalks live. Also, updates will be provided to the NASA News Twitter feed.
To access the feed, visit:
http://www.twitter.com/nasa
As Atlantis' flight wraps up, NASA will update a blog detailing the spacecraft's return to Earth.