WorldDownloader for Minecraft 1.6.6 I use MCP 3.4 http://mcp.ocean-labs.de/index.php/MCP_Releases for decompiling, deobfuscation, recompiling, and reobfuscation. Just install it, follow it's Readme file, put my files in the src/minecraft/net/minecraft/src folder and use the batch or sh scripts.
talmor/WorldDownloader
Clones a Minecraft multiplayer world from a remote server to your singleplayer folder
Java