This Library of Congress site has photographs arranged in chronological order and by subject, plus it contains excellent information about many facets of the war.
Although this site is less authoritative than the Library of Congress site, it is simple to navigate through its huge collection of photos from the war.
Check out this collection of some of Lincoln's memorable quotes, including the texts of his most famous speeches.
This Library of Congress site includes maps, charts and other documents from the period. It's a bit of a challenge to navigate, but full of fascinating information.
Visit this site which features a large number of recordings of popular Civil War music, including the "Battle Hymn of the Republic" and "Taps." You may be surprised to discover that you've heard many of these songs before!
The Civil War was told in poetry and music as well as photos and diaries. This site has dozens of poems written by the men who fought on each side of the conflict.