Duke Nukem Forever is still (*fingers crossed*) on schedule to release June 10 internationally, June 14 in North America. But a select few will get their hands on Duke's long-awaited adventure a bit earlier.
On June 3, Gearbox Software and 2K Games will unleash the Duke Nukem Forever demo on the world, but only to those who have "First Access" rights. That includes people who purchased the Borderlands: Game of the Year re-release and those who pre-ordered Duke Nukem Forever at the right video game retailer. (These retailers.)
Though, I'm sure if you keep an eye on the Facebook and Twitter accounts of people who give out game codes, there may be other opportunities.
So, yes, as of this sentence, Duke Nukem Forever is still shipping on schedule—in a sense—and as long as we survive the next couple weeks, we'll see vaporware turn into a real live playable game.