So, this is a post about modding IC2.
To do so, you'll generally need to decompile it. Firstly you'll need to grab MCP5.0 from http://mcp.ocean-labs.de/index.php/MCP_Releases.
Unzip/extract that file to somewhere. Follow it's instructions and make sure you can decompile the vanilla client and server.
To decompile IC2, you'll need the same mods that you have already: ModLoader, ModLoaderMP, and minecraft forge.
Replace your vanilla jars in the MCP jars folder with the modded ones (avoid any mods other than those three in the jar files).
To decompile IC2, you'll need to add in IC2 to the jars. For this, I normally extract the client and server jars to temporary directories and run "jar uf <path to the right one of minecraft.jar or minecraft_server.jar>" from the temporary extraction directories.
Finally, you'll need the compressed file here http://www.mediafire.com/?xmpgh41i5focmpc (sorry, it's mediafire, but the forums won't accept tar.gz files, and I hate using zip).
This contains two patches (one client, one server) and a script which calls into MCP to decompile, before applying the patches and then decompiling again (successfully, the second time).
I am truly sorry that this is probably a linux/cygwin only solution, but MCP does not want to cooperate in building a useful patching environment, so I've had to work around the fun and games there. More info in my detail post below: http://forum.industrial-craft.…ad&postID=29078#post29078