Water H20 = Life
From Ology - American Museum of Natural History.
Water Resources Outreach Program
"Water-resources topics of all completed posters are drawn in a cartoon format by the same cartoonist. Posters are available in color or black and white. The back sides of the color poster JPEG files contain educational activities: one version for children in grades 3-5 and the other with activities for children in grades 6-8. The black-and-white posters are intended for coloring by children in grades K-5.
Water Science for Schools
From the USGS, this site has information on many aspects of water, along with pictures, data, maps, and an interactive center.
The Water Cycle
From the USGS, this site is the most comprehensive Water Cycle Web site in the world and has a wonderful diagram, which is available in 54 languages.
Hands-on lesson plan for younger students to use and understand the water cycle.
Water Cycle Poster
Have students make their own water cycle poster to involve them and help them to retain more of their knowledge about the water cycle.