UPDATE 25.03.14
Hi all, Oliver here, creator of this project! I never imagined that the work of 15 year-old me would bring this much attention. I am definitely no longer maintaining it. Please feel free to use it however you'd like, as long as you credit me.
The Minecraft Classic Forever project brings you the source to Minecraft 0.30 (Classic) along with the latest version of J-OGG!
The original Minecraft Classic source code is Copyright (c) 2009-2012 Mojang AB. The MinecraftClassicForever source code is licensed under the MIT License.