The NCSE has posted a great article on their website that describes Intelligent Design.

Here is a relevant excerpt:

"ID has been called an "argument from ignorance," as it relies upon a lack of knowledge for its conclusion: Lacking a natural explanation, we assume intelligent cause.

Most scientists would reply that unexplained is not unexplainable, and that "we don't know yet" is a more appropriate response than invoking a cause outside of science."

If you have not already heard it, here is the song I wrote about ID that expresses the same basic sentiment.