From random dungeons, they are located in the chests.

ok so i just dig in caves until i find a dungeon?

yesHusky wrote yeah, ive got two more achievements to do and thats find 5 wovles and Ride a pig with a Saddle, so im just wondering where i could find a saddle.

When digging, you'll have to come accross the mob dungeon (mossy cobble, not hard to miss) and there usually in the chest(s). After that you could duplicate it incase you fail to obtain the achievement or if you know what your doing then never mind. There is a seed where there's a zombie and skeleton spawner above near land but cannot remember the name of it.

if you invite me to your game and i get it i will rep+ you.

You find them in dungeons which are scattered across the map, usually you will find cobble stone with green moss on it where the dungeon is

if anyone can join my server and help me find one id REALLY appreciate it!

Use the seed 888 on a new world and a near by dungeon will have a saddle in.

wheres the dungeon? mind helping me look for it?

In dungeons, try to fins a seed where u spawn next to a dungeon

pm me i maybe have one