Intelligent Design, as far as popularly supported, is effectively Creationism Lite.
It's also important I think to understand that "Creationism" isn't a single view, but can describe several mutually exclusive positions; and even just within the Christian perspective.
What most people know as "Creationism" is actually Young Earth Creationism, that is, the universe was created between 6 and 10 thousand years ago, in the span of six literal 24 hour days.
There is also Old Earth Creationism, including Gap-Theory Creationism, here the days of creation are not literal 24 hour days, but periods of time, here the earth and the universe can be millions, even billions of years old. Thus the six days of creation refer to six stages of creation over the course of a very long period of time, though as far as the creation of life is concerned each moment of creation was a specific act of creation (Darwin's theory of evolution is a no-go here).
Then there is Theistic Evolution, or Evolutionary Creationism. Here the Creation story is not read literally, but rather is understood as chiefly poetic, mythological and/or theological (See the
Framework Hypothesis). The days of creation most likely really do mean six actual days, but it's not to be understood as describing literal history or an offering of a scientific account, but rather offering a theological account through the use of mytho-poetic language. Ordinary, mainstream science is not thrown out, but fully accepted: The universe is about 14 billions years old, and probably began with a big bang, the earth formed about 4.5 billion years ago from the solar accretion disk, life appeared around 3 billions years ago and has evolved since with complex organisms appearing about 500 million years ago during the Precambrian/Cambrian and the course of evolution has been going on ever since.
None of the above constitute as science in my opinion. Theistic Evolution/Evolutionary Creationism is not a scientific position, but a theological one. It simply accepts what the widely accepted scientific accounts offer and, as an act of faith, recognizes that these are the methods and processes by which God has been acting and is acting; no different then any other natural mechanism in the universe. God is present and working through and in the ordinary, mundane mechanisms of the universe as the Creator and the One who sustains all things.
Technically, "Intelligent Design" can describe Theistic Evolution as much as anything else, but that's not what is usually meant, since it is usually set up against evolution, rather than concurrent with it--and either way, it's not science; it's theology.
-CryptoLutheran