"Mars Global Surveyor (MGS) is currently orbiting and observing Mars.
MGS was launched 7 November 1996. It reached Mars 12 September 1997.
The Primary Mission began 9 March 1999, and ended 31 January 2001.
The Extended Mission began immediately on 1 February 2001 and the current plan is for the mission to end in April 2002."
http://www.msss.com/mars/global_surveyor/mgs_moc_MENU.html
"The Extended Mission phase, which starts February 1, 2001, is scheduled to continue to at
least April 2002. During this phase, the MOC team will get to routinely point the
spacecraft to image specific places on Mars, something that was done very infrequently
during the Primary Mission."
http://www.msss.com/mars_images/moc/01_31_01_releases/index.html
"The Mars Global Surveyor (MGS) Extended Mission Phase began February 1, 2001. The main objectives for the Mars Orbiter Camera (MOC) during this busy time include:

continued daily monitoring of martian weather, storms, and polar cap changes;
use of the high resolution camera to seek changes caused by frost, wind, slope movements, and gully action;
re-observe geologic features previously seen by MOC by pointing the spacecraft "off-nadir"---toward the feature---to provide "3-D" (stereoscopic) views; and
obtain pictures of other geologic features of interest, including sites being considered for the two 2003 Mars Exploration Rover landings."
http://www.msss.com/mars_images/moc/extended_may2001/index.html