Women were not as deeply involved in this war as they would come to be in WWII, but they did participate in important ways. Some women served as "camp followers" doing various services for soldiers. A few hundred women disguised themselves as men and fought in the war for some period of time. The two most common ways for women to participate, though, were as nurses and as spies.
On both sides, women were able to serve as spies and in related positions. They were less likely to be challenged and searched by the soldiers than men would have been. As an example of this, a woman named Elizabeth Van Lew built a major spy ring for the Union from her home in Richmond, Virginia.
Even more women served as nurses or other aid workers. This was a role that was more in keeping with the idea of women as nurturers. The famous Clara Barton, who would go on to found the Red Cross, was a nurse in this war. Dorothea Dix, who was a major figure in reform movements before the war, was the Superintendent of Female Nurses for the Union.
In these ways and others, women participated in the war effort for the Civil War.