You probably came here by way of a minecraftforum.net thread. The minecraft.us domain where EarthS*P was originally hosted is gone (no more DNS record), and it looks like I am one of the few to have a copy from when it was available. I am not the author of these maps.
Furthermore, I took the opportunity to also do the map conversion from MCR to MCA since users on said Minecraft forum thread have issues with their operating system, or with patience, or both. For the curious: the conversion took me about 20–25 wallclock minutes (on i7-2600K) and this process used 5600 MB RAM. Machine ran Minecraft Server 1.3.2 on openSUSE 12.2 (Linux) -- the recipe to success.
Disclaimer: Please note that incompetent people will not be able to download or use this properly (and will subsequently leave a post on the forum because they do not know how to read the last pages of a thread).
Mirrored EarthSMP/EarthSSP (the original).