Diamond
Chat with our AI personalities
You can't. But with resource packs or mods you can.
To install a texture pack in minecraft (they are now called 'Resource packs' and can also contain sounds), click 'options', 'resource packs', then 'open resource pack folder'. Place any packs here, then select them in the resource packs menu. Note that 1.5.0 and higher require a different format than 1.4.7 and below.
Foxes are not in minecraft.
The yogscast are one of the most popular minecraft videos
Modloader, Modloader MP, and most Minecraft mods are completely free. You can download most of them at the Minecraft Forum.