now with my up coming skin release i have a lot of mob skins and i dont feel like answering loads of questions about how to make them work so hopefuly this helps.

1. the first thing 2 do is open the mc.jar file and go 2 mobs.

2. click the mobs skin you wish 2 change and deleat it.

3. drag your skin into the mobs file.

4. rename your skin the same as the one you deleated E.G: cow.png. <---IMPORTANT

play mc as usual

NOTICE: this will only work if texture pack is default!!!!!