Gap Theory of Creationism 
This theory is based on the second verse of Genesis 1, where the Bible states that the planet Earth was already here before the creative process of the seven days even began.
http://www.kjvbible.org/What is the "Gap Theory?"
Discussion of the Gap Theory used by some Christians to harmonize the Bible and the geologic record. Describes its history and reasoning.
http://www.christiananswers.net/q-aig/aig-c003.html
Gap Creationism
Wikipedia article on the Gap Theory of creation.
http://en.wikipedia.org/wiki/Gap_Creationism
The Gap Theory of Genesis
A definition and history of gap theory, proof texts and discussion of problems with the theory.
http://www.tlogical.net/gap.htm
Popular Compromises of Creation�The Gap Theory
This site presents both arguments for and against the gap theory.
http://www.apologeticspress.org/articles/442
Gap Theory and/or The Ruin and Reconstruction Theory of Genesis 1
In this theory Gen. 1:1 describes the creation of heaven and the Earth. Millions or billion of years later God renewed the earth as described beginning in Gen. 1:2.
http://reluctant-messenger.com/gap-theory.htm
