1. Dr. Quantum In flatland. This video explains the ideas of the dimensions in a cartoon
2. Carl Sagan talks about a flatland being visited by an Apple (not the computer) and also shows what it would be like for us to interact with a Tesseract.
3. A 4 dimensional cube rotating into our dimension (a Hyper-cube or Tesseract)
4. Additional Notes on Multidimensionality.
5. A panel on Multidimensionality (interesting note: Lawrence Krauss, the ardent Atheist physicist is in this agreeing with Supernatural planes. You may also wish to watch his dismal performance in his debate with William Lane Craig see next item).
(Not related to dimensions) Lawrence Kraus and William Lane Craig Debate