How to install the Mods:
(Video below)

Windows:
1) Open up %appdata%, if you don't know how to do this, start>run, then type in %appdata%
2) Browse to .minecraft/bin
3) Open up minecraft.jar with WinRAR or 7zip. WinRar Is my favourite (<!-- m -->http://rarlab.com/<!-- m -->)
4) Drag and drop the necessary files into the jar.
5) Delete the META-INF folder in the jar.
6) Run Minecraft, enjoy!


Mac:
1) Go to Applications>Utilities and open terminal.
2) Type in the following, line by line:


cd ~
mkdir mctmp
cd mctmp
jar xf ~/Library/Application\ Support/minecraft/bin/minecraft.jar


3) Outside of terminal, copy all the files and folders into the mctmp directory.
4) Back inside terminal, type in the following:


rm META-INF/MOJANG_C.*
jar uf ~/Library/Application\ Support/minecraft/bin/minecraft.jar ./
cd ..
rm -rf mctmp



5) Run Minecraft, enjoy!