Sky cartography software
Stellarium
Stellarium is a free planetarium for your computer. It shows a realistic sky in 3D, just like what you see with the naked eye, binoculars or a telescope. It is the perfect sky map for beginners and for realistic rendering.
Stellarium is written in C++ and is working on most operating systems.
Telescope control
Stellarium has the ability to control telescopes for GoTo operations. It does not check for sun-pointing or mount collision. Two modes of interaction are possible, as explained on the main wiki page for telescope control. The first mode is using a telescope server, a standalone application interacting with the telescope device. It requires command-line interaction and manual configuration. The second mode is using the telescope control plug-in, with its graphical user interface. It connects to the telescope devices either directly, with the serial port, or using the telescope servers from the first method.
The only advantage I see about using a telescope server instead of the direct link is that it can be distributed on the network. The telescope server communicates with Stellarium using a stellarium-specific protocol described here (source).
Here is the list of compatible telescopes with either ways.
Cartes du Ciel (CdC) / SkyChart
XEphem
XEphem is a generic INDI client: Control any INDI-compliant devices with XEphem.
The XmTel package provides the INDI drivers (and an INDI server) for telescopes. It is compatible with XEphem.
KStars
Website. INDI-enabled.
Planetary cartography software
All sky cartography software above are able to depict the phase or appearance of planets of the solar system, or information about their visibility, their satellites, and so on. XEphem has a solar system view that enable visualizing the position of planets in it, easily understanding what happens at what date, or finding conjunctions.
Virtual Moon Atlas
Virtual Moon Atlas is a 13-year running opensource project featuring the visualization of the Moon aspect for every date and hour. Many tools are available, such as measuring, crater identification and so on, and on Windows with ASCOM, it can also pilot computerized telescopes on the Moon surface. See also the Sourceforge project.