Mac: go to the library (go -----) hold down alt) than search for a folder named Minecraft I'm that folder there s one with: texture packs in it drag your texture pack into that folder and you are done! :)

Windows: open up the menu type in there: %appdata% hit enter there should be appear a .minecraft folder open it search for a texture packs folder in it than drag your texture pack folder in it and you are done!

Happy Minecrafting!

-gufuz