The SRTM KML Project has released a very nice network-linked KML which displays shaded relief images derived from Shuttle Radar Topography Mission (SRTM) digital elevation models in Google Earth. Their website reports:
This version covers the entire SRTM dataset (80% of the land on the Earth). It is based on the SRTM V2 product. A new "fill" algorithm was developed at CCIC, which significantly improved the cartographic quality of the layer without compromising the accuracy.
The global SRTM shaded relief KML file can be downloaded from: http://srtmkml.googlepages.com/