Although biting seems primitive and violent, keep in mind that most all human behavior serves a purpose.  In the classroom, perhaps the child is biting because this enables him to get what he wants.  It is also very probable that the child is able to express himself through biting.  If he is preverbal or not very articulate, he may be conveying feelings of frustration, fear or lack of control.
The recommendation that you shadow a child that is exhibiting biting behavior is a good one.  Sometimes inappropriate behavior is pretty puzzling.  By gaining a good and thorough knowledge of the circumstances in this situation you will be able to work more effectively with the child.    
In order to change behavior you must know the antecedent conditions (what happens before the behavior occurs) and the consequences of the behavior (what happens after the behavior has occurred).  Think back to the times when the biting has occurred.  Review the environment of the classroom before the biting took place.   Take note of the activity level, the child’s behavior, the behavior of the other children.  Be mindful of your own behavior.  Were you working with another student?  Were you within arm’s reach of the child or further away?    What happened directly after the biting took place?  Was there a punishment; was the child removed from the area?  How did you and the other children respond?  
 Once you have had the opportunity to review the before and after of the biting episodes, you will be much better equipped to change this pattern of behavior.    There are many possible variables that you might be able to manipulate.  For instance, is he only biting when in a free play situation?  Does his behavior result in gaining your attention or getting what he wants from another student?  Many of the classroom conditions could be changed to provide the child and you with an outcome that is more acceptable.  
Children will learn and behave best with structure and consistency.  Do not be afraid to set the rules of the classroom to protect all of the children.  Do you need to have a certain area marked for the child so that he is better able to be monitored?  Are children allowed to play with whatever they would like or are there rules regarding time limits or a rotation of the toys?   Are you teaching all of the children the appropriate means of gaining your attention?
Are there immediate rewards if the child is doing well?  Conversely, what happens when he bites?  If the child is gaining all of your attention after hurting another child, is there a way that you could spend some extra time with him before the biting typically occurs?
The answer to your question is really as varied as the number of children that engage in the behavior.  Remember that the behavior serves a purpose and that you can change what is happening before and after to decrease or eliminate the behavior.