Minecraft 1.6+ radically changed the layout of minecraft's jar files, with the versions folder and everything. As a result, Forge now has an auto-installer (Yay, no more manual surgery on the main game file!) As another result, people are confused because they are used to how it was done in 1.5 and earlier.
One of the better threads on how to install Forge and load Forge mods, and/or how to make a modded version of the minecraft jar file (for those mods that still require manual surgery) needs to be stickied, so we don't continue to have dozens of threads consisting of "Help! I can't mod 1.6.1!".
Please? Pretty please? Pretty please with sugar on top?