If you need to find the distance between two points, the distance finder buried on the Indonesian tourism page (www.indo.com/distance/) has always been a good first stop.
There's also another I've discovered, put out by Geobytes at http://www.geobytes.com/CityDistanceTool.htm
There are always some slight variations. For Columbia to Biloxi, for instance, Indo shows 533 miles and Geobytes 523. But that gets you close enough for most stories. And remember, these are "as-the-crow-flies" distances, not driving distances. Still, for most stories, that's what you want anyhow.
(Geobytes specializes in code that customizes Web sites based on the browser's location.)