Many people get theistic evolution and intelligent design mixed up. It's not accurate to portray theistic evolutionists as supporters of the intelligent design (ID) movement, nor is it accurate to portray ID advocates as those who completely accept evolution.
Both believe that there is design in nature, that God created the universe. However, it is only ID advocates which claim that there's some sort of scientific basis for this belief. A theistic evolutionist would say that while design in nature can be inferred, it can not be scientifically established.
The ID movement is an attempt to undermine science by saying that natural processes are not sufficient to produce what we see in nature, i.e. supernatural miracles are required (or aliens, or some other intelligent interference). They may hold up "irreducibly complex" systems as evidence that some sort of interference or help was needed along the way. Theistic evolutionists accept that natural processes are sufficient (though they may believe God could intervene in a more direct manner if he wanted to) and that irreducibly complex systems do have a natural explanation.
ID advocates seem to think that either something is naturally designed, or intelligently designed, and they seem to set it up in such a way that both can't be true. The ID movement, as promoted by many Christians, basically says "I don't know how this could have happened naturally, so God did it." This is an argument from incredulity, and puts God into gaps that will inevitably be filled one day.
Theistic evolutionists believe that God can work through nature to exert His will in a situation. While nature is believed to be created, natural processes are a sufficient tool for that creation, or at least the primary one.
The most major difference between ID advocates and theistic evolutionists are their views on public school education. ID advocates have been going to court to get their beliefs taught as science in science classrooms. Most theistic evolutionists would be opposed to this happening.
Creationists often take well to ID style arguments, while they reject theistic evolution as being false. One can be a creationist and an ID advocate at the same time, while a theistic evolutionist always accepts evolution.
Below is summary of the above points, comparing atheistic evolution, theistic evolution, and intelligent design.
Is nature designed/created by God (or other conscious intelligence)?
AE: No TE: Yes ID: Yes
Can nature's design by an intelligent being/beings be scientifically established?
AE: No TE: No ID: Yes
Are natural processes sufficient to produce the designs we see in nature?
AE: Yes TE: Yes ID: No
Should the role of an intelligent designer in nature's creation be taught in public schools as science?
AE: No TE: No ID: Yes
Can you be a creationist (one who rejects evolution and believes in special creation) and still hold this position?
AE: No TE: No ID: Yes
My POTM:
The Talk.Origins Archive Post of the Month: January 2003
There were some people at the MSN EvC group that helped vote for me. 
™ Version 4.2