First, you're going to need to download and install the latest version of WinRAR, which can be found here:
1. Download Rigusami's Modloader from here:
This will allow the installation of multiple mods.
2. Find the mod(s) that you would like to add to Minecraft, and download them.
3. After downloading, navigate to your Minecraft folder by typing in %appdata% in your search bar and pressing enter, then selecting the .minecraft folder.
4. Go to the bin folder, right click on minecraft.jar and select Open With > WinRAR Archiver.
5. Once opened, delete the META-INF folder inside. Then, find the .zip or .rar for the Modloader, open and select all of the files, and drag and drop them into the minecraft JAR file.
6. Then, you can proceed to add the rest of the mods you'd like in the same manner.
7. Close all WinRAR tabs, and start up Minecraft. If you see the Mojang logo after logging in, you've done it correctly!
Good post and it's very noob friendly for those scrubs out there!
I had trouble with this til now, thanks!