Ross's Planetary KML

Now that Google, Inc., has launched Google Earth 5.0 with a real Mars mode (initial launch blog post and update post), you don't have to try and fake it like this Orrery.us article explains. However, if you want to wrap other planetary basemaps, that is still one way to go about it.

The KML files that you can download on this page may point to one of our servers at Ames (especially the big overlays), and should be considered "draft" KML. They could go away, be renamed, or removed at any time. These are mostly just experiments to see what we can do with Planetary data and KML. Enjoy!

Mars Global Surveyor (MGS)

MOC Footprints DEPRECATED now that they are in Google Earth's Mars mode
These data are from the Mars Orbiter Camera (MOC) Narrow Angle Camera on board the Mars Global Surveyor (MGS) as released through the Plane tary Data System (PDS). The coordinates for these footprints were provided by Kris Becker, of the USGS, via a beta version of the Unified Planetary Coordinates Database.
TES Thermal Inertia from Christensen et al. 2001
This map was taken from the "global map without MOLA" PNG at http://jmars.asu.edu/data/tes_ti/. That map was published in Christensen et al., The Mars Global Surveyor Thermal Emission Spectrometer experiment: Investigation description and surface science results, J. Geophys. Res., 106, 23,823-23,871, 2001. [PDF]
Nightside TES Thermal Inertia from Putzig and Mellon 2007
This map was taken from the "Night Thermal Intertia" .bin file at http://lasp.colorado.edu/inertia/2007/, and logarithmically scaled. That data was published as figure 8 in Putzig and Mellon, Apparent thermal inertia and the surface heterogeneity of Mars, Icarus 191, p. 68-94, 2007. doi: 10.1016/j.icarus.2007.05.013
Dayside TES Thermal Inertia from Putzig and Mellon 2007
This map was taken from the "Day Thermal Intertia" .bin file at http://lasp.colorado.edu/inertia/2007/, and logarithmically scaled. That data was published as figure 8 in Putzig and Mellon, Apparent thermal inertia and the surface heterogeneity of Mars, Icarus 191, p. 68-94, 2007. doi: 10.1016/j.icarus.2007.05.013

Mars Odyssey

THEMIS Night IR Global Mosaic DEPRECATED now that this is in Google Earth's Mars mode
This map was taken from the tiles at http://jmars.asu.edu/data/themis_nightir/.

Mars Express

DEPRECATED since these footprints are in Google Earth's Mars mode, as is overlaid imagery on the burned-in basemap, and the HRSC terrain is incorporated into the Terrain feature.

HRSC Nadir (ND3) footprints
These data are from the High Resolution Stereo Camera (HRSC) on board the Mars Express Spacecraft as released through the Planetary Data System (PDS). Since most of the other HRSC line scanners are on during any particular observation, I figured that the nadir set would be representative to determine coverage. Once you know a particular spot is covered by a nadir observation, it is easy to find the data from the other scanners on the same orbit.
HRSC DTM (DT4) footprints
The HRSC team has started releasing digital terrain models (DTMs) built from their stereo imagery, and these are their locations. It seems like the footprint outlines in the PDS-distributed cumindex.tab file are those of the parent images, and sometimes the area actually covered by the DTM is less than what this coverage KML might show.

Mars Reconnaissance Orbiter

HiRISE Footprints
These data are from the High Resolution Imaging Science Experiment (HiRISE) on board the Mars Reconnaissance Orbiter (MRO) as released through the Planetary Data System (PDS). Although HiRISE footprints are in Google Earth, they are not currently being updated weekly, as this KML is.
CTX Footprints DEPRECATED now that they are in Google Earth's Mars mode
These data are from the Context Camera (CTX) on board the Mars Reconnaissance Orbiter (MRO) as released through the Planetary Data System (PDS).
SHARAD Tracks
These data are from the Mars Shallow Subsurface Radar (SHARAD) on board the Mare Reconnaissance Orbiter (MRO) as released through the Planetary Data System (PDS). This is not up-to-date with the PDS releases, because I'm not sure anyone finds it useful.

Landers

Phoenix landing ellipses DEPRECATED now that this information is in Google Earth's Mars mode
This includes the actual location of the Phoenix spacecraft, and the 1, 2, and 3 sigma landing ellipses.
MSL landing Sites
This page, curated by Eldar Noe of JPL, hosted at UCSC, contains lots of great KML data for the MSL landing site selection process.