From their website, Intercaching Home....
I just finished listening to an interview with the creator, ChileHead, about it on GeoGearHeads episode 75. I'm going to investigate it and try to create on for OCNA. I think it will be listed as an "Unknown", since it doesn't fit another established cache type.An InterCache is an interactive geocache. A geocache is an outdoor activity that uses GPS devices to play a high tech treasure hunt. See geocaching.com for more information. An intercache is a new way of creating a mystery geocache, similar to a wherigo geocache. The biggest difference is that the entire geocache can be developed, edited, and played on your mobile phone's browser with no software required to download!
Part virtual cache, part multicache, part puzzle cache, and part wherigo. What can you do with it?
I thought I'd heard it discussed on another podcast, recently, but can't find it.