Linux software
Celestia (space simulation) -
http://www.shatters.net/celestia/index.html
Stellarium (planetarium software) -
http://www.stellarium.org/
Where is M13? (three-dimensional galactic atlas) -
http://www.thinkastronomy.com/M13/index.html
XEphem (star-charting and ephemeris-generating software) -
http://www.clearskyinstitute.com/xephem/xephem.html
KStars
http://edu.kde.org/kstars/
xsat 1.5 - A Satellite Tracker for the X Window System
http://www.astrotrf.com/xsat.html

Mac software

AstroPlanner (planning and logging software) -
http://www.ilangainc.com/astroplanner/index.html
Celestia (space simulation) -
http://www.shatters.net/celestia/index.html
DarkAdapted (gamma control software to preserve night vision) -
http://www.adpartnership.net/DarkAdapted/index.html
Equinox (planetarium program) -
http://www.microprojects.ca/equinox6.html
Photographic Moon Book (lunar observations - PDF format; Mac compatible?) -
http://www.alanchuhk.com/
Starry Night (planetarium software) -
http://www.starrynight.com/
Stellarium (planetarium software) -
http://www.stellarium.org/
Where is M13? (three-dimensional galactic atlas) -
http://www.thinkastronomy.com/M13/index.html
XEphem (star-charting and ephemeris-generating software) -
http://www.clearskyinstitute.com/xephem/xephem.html
Scope Driver - Observing management and telescope control -
http://www.adpartnership.net/ScopeDriver/
Voyager IV - Astro plotting and telescope control -
http://www.carinasoft.com/voyager4/index.html
Keith's Image Stacker - Astro image processing and stacking -
http://www.cs.unm.edu/~kwiley/software/keithsImageStacker.html
iAstrioPhoto - DSLR focus and control for astrophotgraphy -
http://homepage.mac.com/stevepur/astrophotography/iAstroPhoto/
PHDGuiding - software to control autoguiders -
http://www.stark-labs.com/phdguiding.html
DSLR Shutter - Control DSLR exposures
http://www.stark-labs.com/DSLR_Shutter.html
Nebulosity Astrophotography Software
http://www.stark-labs.com/nebulosity.html
Redshift
http://www.redshift.de/
Lunar Discoverer
http://www.astrohawk.com/

Windows software

AstroPlanner (planning and logging software) -
http://www.ilangainc.com/astroplanner/index.html
Cartes du Ciel (sky charting and planning software) -
http://www.stargazing.net/astropc/
Celestia (space simulation) -
http://www.shatters.net/celestia/index.html
CnebulaX (charting, planning software) -
http://www.uv.es/jrtorres/CNebulaX.htm
DarkAdapted (gamma control software to preserve night vision) -
http://www.adpartnership.net/DarkAdapted/index.html
DeepSky (planning and logging software) -
http://www.deepsky2000.net/features.htm
Deep-Sky Planner (planning and logging software) -
http://knightware.biz/dsp/
DeepSkyStacker (image processing software) -
http://deepskystacker.free.fr/english/index.html
GraphDark (planning software) -
http://home.clara.net/rfleet/graphdark/gdkindex.html
Guide (planning software) -
http://www.projectpluto.com/
GuideStar LX200 Software Emulator (emulator for autoguiding using DSI/LPI) -
http://www.skyinsight.net/wiki/index.php/GuideStar_LX200_Software_Emulator
HNSKY (planetarium software) -
http://hnsky.org/software.htm
Jupiter (calculate Jupiter satellites ephemeris) -
http://astrosurf.com/rondi/jupiter/
JupSat Pro (Jupiter and moon planning software) -
http://www.nightskyobserver.com/JupSatPro/
K3CCDTOOLS (video/image processing software) -
http://www.pk3.org/Astro/
LunarPhase Pro (interactive Moon atlas)
http://lunarphasepro.nightskyobserver.com/
MegaStar (sky atlas) -
http://www.willbell.com/software/megastar/index.htm
NASA World Wind (experience Earth terrain in visually rich 3D) -
http://worldwind.arc.nasa.gov/
NightCal (Moon phase software) -
http://www.nightcal.co.uk/
Orbiter (space flight simulator) -
http://orbit.medphys.ucl.ac.uk/orbit.html
Photographic Moon Book (lunar observations) -
http://www.alanchuhk.com/
Pocket Stars (star chart software) -
http://www.nomadelectronics.com/PocketPC/PocketStars/PocketStarsPCIntro.htm
RegiStax (image processing software) -
http://registax.astronomy.net/
RTGUI (planning software) -
http://www.debunker.com/astro/rtguipage.html
Sky Map (star charting and planetarium software) -
http://www.skymap.com/
SkyTools (planning and logging software) -
http://www.skyhound.com/skytools.html
StarCalc (planetarium star mapping program) -
http://www.relex.ru/~zalex/
Starry Night (planetarium software) -
http://www.starrynight.com/
Stellarium (planetarium software) -
http://www.stellarium.org/
Tachyon (planetarium and scope control software) -
http://tachyonweb.net/
TheSky6 (planetarium software) -
http://www.bisque.com/Products/TheSky6/
Virtual Moon Atlas (moon observation software) -
http://astrosurf.com/avl/UK_index.html
Where is M13? (three-dimensional galactic atlas) -
http://www.thinkastronomy.com/M13/index.html
Nebulosity Astrophotography Software
http://www.stark-labs.com/nebulosity.html
Focus Magic
http://www.download.com/Focus-Magic/3000-12511_4-10054317.html
Autoguide Assistant
http://www.dougsastro.net/AutoguideAssistant/AutoguideAssistant.php
Lunar Discoverer and Lunar Pronouncer
http://www.astrohawk.com/

Palm

Astromist (planning software) -
http://www.astromist.com/
Planetarium (planning software) -
http://www.aho.ch/pilotplanets/

PocketPC

Pocket StarCalc (planetarium program) -
http://www.relex.ru/PocketStarCalc/
Pocket Stars (star chart software) -
http://www.nomadelectronics.com/
Tachyon (planetarium and scope control software) -
http://tachyonweb.net/
TheSky (planetarium software) -
http://www.bisque.com/Products/TheSkyPE/TheSkyPE.asp

Websites with lists/links of software

Astronomy Links -
http://astronomylinks.com/software/
AstroTips -
http://www.astrotips.com/
Linux Links -
http://www.linuxlinks.com/Software/Scientific/Astronomy/
MacAstonomy -
http://www.macastronomy.com/
Planetarium Software -
http://astro.nineplanets.org/astrosoftware.html

Other

Observation Manager -
http://observation.sourceforge.net/
CCDWare - Makers of PEMPro, CCD AutoPilot, and CCDStack -
http://www.ccdware.com/
FocusMax (ASCOM compliant focuser control) -
http://users.bsdwebsolutions.com/~larryweber/
The Full Moon Atlas (interactive Moon maps) -
http://www.lunarrepublic.com/atlas/index.shtml
Hartmann mask template generator -
http://billyard.servehttp.com/Hartmann.html
PoleAlignMax (polar alignment refinement) -
http://users.bsdwebsolutions.com/~larryweber/
WCS (WebCamScheinern) (drift alignment with a CCD or webcam) -
http://wcs.ruthner.at/index-en.htm