There are 3 or 4 other threads about this in the fishing forum.
It's a drawing. There are three prizes, a $200 gift card, a 2013 Maryland State Parks Pass (free entry to any state park for a year), and a 2013 Potomac River Fishing License. In order to be considered, you need to put a picture of yourself and the snakehead(s) on the MD DNR's Angler's Log. I believe that every angler's log entry is an entry to the drawing, but I'm not 100% positive on that. It's just an effort to push snakehead fishing to the forefront and get people interested in catching and killing them. There are lots of folks on here who believe that killing the snakeheads in MD is wrong, but I'm not getting into that on this thread, there is plenty of that in the fishing forum as it is.
The bottom line is that they're a fun fish to catch, they're great eating and you could win a prize. It seems like a pretty good deal to me!