Here are a few links to individuals, organizations that I think are especially important and helpful:

• Wikipedia on Near-Death Experiences
• International Association for Near-Death Studies
• The Journal of Near-Death Studies
• Near Death Experience Research Foundation
• Near-Death Experiences & The After Life
• University of Virginia Division of Perceptual Studies
• Survival Research Network
• Near-Death Experience Experts
• The AMerican Center for the Integration of Spiritually Transformative Experiences