Not sure if this has been posted before, I couldn't find it however so I'm posting it.
Alright this is how to get at the bottem of the pit under Sunfury Spire.
Start by going on the hedge around Sunfury Spire. It's possible to do this at the left and the right side, but I'm showing you the left one. It's easy to get on from the bench I'm standing on in the picture.
Okay, now walk to the wall.
Time for a little wall jumping. Two jumps should be enough.
Now just walk to the right, ready to make the jump. Don't forget to take your armor off unless you want 10% durability damage.
Oh noes, I slipped! Now I'm gonna die. Unless you don't have a cooldown on your hearthstone I recommend you to ress at the spirit healer.