The most famous taxonomy of educational objectives was created by Benjamin Bloom back in the fifties and has been tweaked ever since. Just google "Bloom's taxonomy" and you will get tons of hits. One of my favorite taxonomies was developed more recently by Yager. However, a caution. These things are human-created models and are not written in stone. Their purpose was to help teachers think about a variety of levels of instructional objectives in order to plan classroom instruction that is balanced and not focused entirely on the bottom "recall" level. No Child Left Behind and high-stakes testing have pushed instruction back to that lowest level of objective however, which is a shame.