It's a new game that should close the Dreamfall story. They also intend to make another game to close The Longest Journey's story.

It's a whole new game.

Edit:ninja-ed

i thought dreamfall was the sequel to the longest journey

i have both but i have yet to play them

Two intertwined stories. They do share the same universe.

Well, Telltale did give Back to the Future Ep. 1 for free few years ago, to promote the following episodes. They did the same with Sam&Max too, although in that case the free episode was from the middle of the season.

Some other games have the same free introduction model too. The first part of Reversion has always been free (AFAIK), but the next one(s) must be purchased. AR-K had the first part available for free to promote their Kickstarter for the rest of the game.

So it's definitely possible that it's free.
Of course, it's also kind of unlikely since the rumor has it that they need money from the first chapter to maintain the production values of the following chapters.

KInda got my heart racing there, I have the original box TLJ and a box set of TLJ and DF together, picked up TLJ on Steam awhile back for the princely sum of €1.50, so it would be nice to get a free DF digital copy so I can retire the discs.

And just to make sure I have this correct (I remember Dreamfall / TLJ from my console days - at the time it was very well regarded and one of the only adventure games on the consoles - I wasn't very interested in the PnC / Adventure style - and I'm a long time PC gamer - but GoG has since made me go back and check a few out)

The Longest Journey is the first game

Dreamfall: The Longest Journey is the second? Not a remastered or original + new content "bundle"?

I get confused as it's odd to have a "subtitle" be the title of the original game. Also - these are distinct from the Syberia games yes?

The Longest Journey is the first game.
Dreamfall is the sequel, a new story but still with April.
Both are distinct of the Syberia serie.

Totally distinct from Syberia. Different lead developers, different studios, different everything. The only common factor is a female protagonist.

As for TLJ/Dreamfall. The Longest Journey is the first game, and has April Ryan as the protagonist. Dreamfall: The Longest Journey is the second game (though not exactly a sequel), taking place some years after The Longest Journey. It is set in the same two worlds (Stark and Arcadia), but Zoe is the lead character with April and... that guy whose name I forgot being the secondary characters. Dreamfall Chapters is the third game, with Zoe again being the lead (as far as we know).

I wish, it would be cool if they gave the other games in the series for free in order to promote the new game.

Here you can see the various prices for each edition, set by the developers.

It also says "The first episode of Dreamfall Chapters — Book One: Reborn — is scheduled for release in autumn 2014".
That is soon.