Impact: Earth! is a visual and user-friendly impact calculator, developed and hosted by Purdue University. The original Earth Impact Effects Program is still available to calculate the effects a given distance from an impact. It uses exactly the same algorithms to estimate the impact effects. You can also try out a version of the original program that is still under development to map the effects of an impact somewhere on Earth. Note this site requires the Google Earth plug-in and is still being tested.
WANDERLUST 