I found a good article on this subject:
http://www.christiancourier.com/articles/559-does-god-change-his-mind
I was preparing for a bible study from I Samuel ch 15 and came across what could appear to be a contradiction within the chapter:
1Sa 15:29 And also the Strength of Israel will not lie nor repent: for he is not a man, that he should repent.
1Sa 15:35 And Samuel came no more to see Saul until the day of his death: nevertheless Samuel mourned for Saul: and the LORD repented that he had made Saul king over Israel.
THERE ARE SEVERAL VERSES ON BOTH SIDES OF THE ISSUE:
GOD DOES NOT REPENT:
Numbers 3:19
God is not a man that he should lie; neither the son of a man that he should repent.
Numbers 23:19 God is not a man, that he should lie; neither the son of man, that he should repent: hath he said, and shall he not do it? or hath he spoken, and shall he not make it good?
1 Samuel 15:29
The Strength of Israel will not lie nor repent: for he is not a man, that he should repent.
Ezekiel 24:14
I the LORD have spoken it: it shall come to pass, and I will do it; I will not go back, neither will I spare, neither will I repent.
Malachi 3:6
For I am the Lord, I change not.
James 1:17
With whom is no variableness, neither shadow of turning.
GOD REPENTS:
Genesis 6:6
And it repented the Lord that he had made man on the earth, and it grieved him at his heart.
Exodus 32:14
And the Lord repented of the evil which he thought to do unto his people.
Deuteronomy 32:36
For the Lord shall judge his people, and repent himself for his servants.
1 Samuel 15:11
It repenteth me [God] that I have set up Saul to be king.
1 Samuel 15:35
The Lord repented that he had made Saul king over Israel.
2 Samuel 24:16
The Lord repented of the evil, and said to the angel that destroyed the people, it is enough: stay now thine hand.
1 Chronicles 21:15
The Lord beheld, and he repented him of the evil, and said to the angel that destroyed, It is enough, stay now thine hand.
Isaiah 38:1-5
In those days was Hezekiah sick unto death. And Isaiah ... said unto him, Thus saith the LORD, Set thine house in order: for thou shalt die, and not live. ... Thus saith the LORD ... I have heard thy prayer, I have seen thy tears: behold, I will add unto thy days fifteen years.
Jeremiah 15:6
I [God] am weary of repenting.
Jeremaih 18:8
I [God] will repent of the evil that I thought to do unto them.
Jeremaih 26:3
That I [God]may repent me of the evil, which I purpose to do unto them.
Jeremiah 26:13
The Lord will repent him of the evil that he hath pronounced against you.
Jeremiah 26:19
The Lord repented him of the evil which he had pronounced against them.
Jeremaih 42:10
For I [God] repent me of the evil that I have done unto you.
Amos 7:3, 6
The Lord repented for this.
Jonah 3:10
God repented of the evil, that he had said that he would do unto them.