Intelligent Design
The theory of intelligent design holds that certain features of the universe and of living things are best explained by an intelligent cause, not an undirected process such as natural selection.  Intelligent Design Theory (IDT) is sometimes called "creationism in a cheap tuxedo" or “creationism's trojan horse” because IDT shares some common elements with the creationism. However IDT is not exactly the same as creationism.

IDT is developed from purely scientific principles without reference specific reference to religious texts, deities, age of the Earth, or special creation.  IDT does not officially insist that the Intelligent Designer is the Christian God, nor insist that the Earth is young, nor automatically reject common descent.

IDT was spearheaded by a rather peculiar alliance of atheists, agnostics, and creationists who rejected Darwinism and accidental life origins.  For example, the most prominent atheist Intelligent Design advocate is cosmologist Frank Tipler, and the most prominent agnostic Intelligent Design advocate (or at least sympathetic) is molecular genetecist Michael Denton, MD, PhD.  They are allied with theists like mathematician William Dembski, biochemist Michael Behe, and biologist Johnatha Wells and Christian Creationists like Paul Nelson.

The grandfather of modern Intelligent Design we claim is  Michael Polanyi who was mentor to Nobel Laureate Eugene Wigner and Nobel Laureate John Polanyi.  Eugene Wigner formed the basis of much of the physics behind Intelligent Design.  Intelligent Design is basically an interpretation of the science of Quantum Mechanics.
 

Creationism
Creationism is the belief that the origin of the universe is described by the Genesis account of Adam and Eve.  There are several varieties of creationism including Young Earth Creationism (YEC) which interprets the Genesis creation as happening in six 24-hour days, and several varieties Old Earth Creationism (OEC) which interprets Genesis as spanning a time frame of billions of years.  Most forms of Creationism accept Noah's Flood.  A heavy dose of Intelligent Design Theory is important to understanding the scientific evidence supporting creationism.