There are two major forms of creationism,Young Earth Creationism and Old Earth Creationism as they are called. Young Earth creationists hold the view that the earth is 6,000 to 10,000 years old and created much as it is now. This includes the view that all life was created simultaneously and no major changes (eg Speciation) has taken place in the intervening time. As opposed to this the Old Earth creationists accept that the Earth is 4.5billion years old but do not agree with a strict materialistic view of the origin of life.

While Old Earth creationism may be considered a philosophical position that tries to allow room for the spiritual as well as scientific evidence, there is no way for Young Earth creationism to be anything more than a religious belief. Young Earth creationists are ideologically bound to reject the evidence for an old Earth and Universe as shown by such lines of evidence as radioactive decay, geological formations, Arctic ice records, genomic mutation rates, plate tectonics, star formation and life cycles and the cosmic microwave background radiation.

Old Earth creationists on the other hand can fall on a spectrum between a literal creation sequence up to accepting all of evolution. This puts many on a semi-equal footing with most non-theistic scientists and they avoid the trap of Young Earthers that pits them against much of modern science. Ultimately the more of the scientific consensus you accept the less of a creationist you become. For some this implies there is no room for god, but that is still a decision that evidence can not help with.

Resources:

http://en.wikipedia.org/wiki/Creationism

http://www.talkorigins.org/faqs/wic.html

http://www.natcenscied.org/ -Link edited for brevity.

http://assembly.coe.int/ -Link edited for brevity.