The mission was outlined at a meeting of the American Astronomical Society (AAS) in Austin, Texas earlier this week...

"The 11-day shuttle mission features five spacewalks. During those spacewalks, astronauts will install two powerful new science instruments, a new set of the gyroscopes that help stabilize the telescope, and batteries and thermal blankets to extend Hubble's operational life until at least 2013. Also, if all goes well, a degrading Fine Guidance Sensor unit, one of three aboard Hubble, will be replaced with a refurbished unit to help maintain the telescope's ability to point and focus on astronomical objects throughout the universe...Astronauts will attempt the first ever on-orbit repair of two existing instruments - the Space Telescope Imaging Spectrograph (STIS) and the Advanced Camera for Surveys (ACS). The ACS was the most-used instrument on the telescope until its failure last January after five years of operations. The STIS - the most sophisticated spectrograph ever on Hubble - took detailed pictures of celestial objects and separated light into its components to diagnose the physical conditions of galaxies, stars, planets and nebulae."

"As both an astronaut and an astronomer, the opportunity to go back to Hubble is more than a dream come true,” said John Grunsfeld, who will be the mission's lead spacewalker. “This mission promises to be quite challenging. NASA has put together the most experienced Hubble crew ever, with three Hubble veterans. The crew and mission team are in full throttle training, looking forward to launch and the hard work of servicing Hubble."

NASA

I really hope they have some luck repairing the ACS.
Long live Hubble!
Regards, Vince