Well, first let me make one thing clear, English is not my native language, I speak Spanish, but I try to write with the help of Google translator, so if some words will not understand why. Ok, first of all, I am new to making mods, I have things well in hand, I made models of the mobs, I have the programs necessary for granting crafteos make and recipes (MCREATOR) which I would like to know ... is that I want to put a flying mob that can be mountable, and I read that deveria copy the files from the Ghast and Pig or seat, but do not know where these files are and how I can open them, also not that I can edit program . That alone would know by now, where I find the files. Well, I hope you help me with this first problem, otravez, I apologize if it is not well understood. Well, thanks
But maybe you'll have more success in finding anyone able to help you when posting this question in the right place, here:
http://www.minecraftforum.net/forum/243-mapping-and-modding-tutorials/