Hi! I've been searching around on unity answers for a very simple AI script that should make the object to patrol between two different waypoints. Try to make it simple and explain, since i'm very new to unity.
http://www.youtube.com/watch?v=UR34z8tbIZA&feature=channel_video_title
In the link, the video creator makes a solid state machine in c# to control the patrol patterns of some wolves.
http://www.youtube.com/watch?v=POUbAsr-6q4&feature=relmfu
In this link, he introduces some AI concepts in Unity.
http://www.youtube.com/watch?v=iMlkC_IKDrQ
here is a video specifically dedicated to AI patrol in Unity.
http://www.freecreationgames.net/Unity/TUTORIAL_ARTIFICIAL_INTELIGENCE.rar
And finally, here is the code for AI Patrols in unity. Already Written. (not by me)
http://www.unifycommunity.com/wiki/index.php?title=CSharp_Unity_Tutorial If the c# is offputting, here is A basic tutorial of programming in C#. I recommend it.
A better place for finding scripts is the forum or the wiki.
http://www.unifycommunity.com/wiki/index.php?title=Scripts
http://forum.unity3d.com/forums/12-Scripting
Try the seek steer found here. http://www.unifycommunity.com/wiki/index.php?title=SeekSteer