julian sprung's book on corals (forget the exact title, i can get it for you if you want) has some of the best photos i have seen. there is also a 3 book series called corals of the world or something like that, hundreds and hundreds of pages of photos, online around 120 bucks for the three. dilbeek has a couple books out on aquarium inverts, one in corals, and one on everything else, also with great photos.
for pics of specific things though, i just go to google, click on images, and then type in what i am looking for... usually yields hundreds if not thousands of images. if you have broadband, 2 or 3 minutes of looking through the images that pop up will find you as good a picture of just about anything that you will find anywhere else.
