A while back there was a big deal on some of the aviation forums about flightprep threatening designers of flight planning & gps software with patent lawsuits & a lot of websites either shut down or started paying royalties to flightprep for what I personally believe is an invalid patent.

While not directly related, anyone who was affected by that situation might be interested in this article:

http://www.washingtonpost.com/blogs/...rite-podcasts/