Colored Creatures is a mod that lets you tame/breed several minecraft creatures. If you breed them they will have colored babies that grow up. Chickens, cows, pigs, spiders, zombies, skeletons and creeper can be bred. The hostile mobs can fight for you if you breed and tame them!
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.
4) Drag and drop all files of the client mod (folder: jar files) into the jar.
5) Delete the META-INF folder in the jar.
6) Run Minecraft, enjoy!