Division of Nuclear Physics (DNP) is comprised of scientists who study fundamental problems related to the nature of matter.
The Department of Energy's Office of Nuclear Physics is the largest funding agency for Nuclear Physics.
The National Science Foundation is a big supporter of Nuclear Physics.
The Radiochemistry Society has a website with an excellent glossary and "Kid's Korner".
CERN has produced a great site called The Search for Antimatter. You can discover what antimatter is, where it is made, and how it is involved within our lives.
A group in Sweden put together the "Radioactive Orchestra". On the site you can "play a musical tune" using the decay properties of an isotope. It requires a browser flash but this video is available for all to watch.
This video documents the discovery of new elements in hydrogen bomb debris. The team of Lawrence Berkeley National Laboratory sciences in this video includes Nobel Prize winner Glenn Seaborg and famed element hunter Albert Ghisoro. LBNL scientist Claude Lyneis uploaded this video to youtube.
Science Buddies is a non-profit organization that helps students and teachers by putting them in touch with experts.
TUNL is a research facility on the Duke University campus that is operated by UNC, Duke, NC State, and NCCU. They link to both their research as well as other interesting nuclear science work.
Read about NASA's research on dark matter. For a more simplified version, explore their Imagine the Universe page.