"As soon as you begin to look at our bodies from an evolutionary perspective you see more and more we are not intelligently designed." ~ Paul Sherman, PhD
Much of the evidence for evolution takes time and interest to learn. How we know evolution is true comes from many independent areas of science including genetics, paleontology, geology, biogeography, developmental biology and many more.
Evidence from our own bodies is easier to access and understand for many. After presenting some fairly simple observations about our own anatomy to a high school biology class that is best explained by evolution, it became clear that others may find these observations interesting also. It's 36 minutes long and a fun way to look at how our past evolution has produced some amazing and often hilarious work-arounds to solve issues that came up during our development as a species. Many of these examples can be found in my blog entry on Unintelligent Design. For more convincing evidence for evolution that presents similar visual evidence especially see the videos on whale evolution. For evolution evidence that rises to the level of near proof, see the blogs and section entries discussing the DNA evidence for evolution, macroevolution.