This site holds the tools I've created for my Savage Worlds space-based Science Fiction RPG. It may not be as useful for your average ordinary person, but it's very helpful for my players and me! Eventually, I'll modify it to allow any type of destination to be plugged in, as a time calculation device. It's great for shipping costs, too!
Meanwhile, these tools may be out of date, broken, or halfway between modifications; a more stable version can be found at the blog, which is somewhat more likely to be in better shape.