It's finally released on Steam, although it's worth noting that the second half of the expansion won't appear until "this Winter".
I've got no doubt that Pillars of Eternity will probably almost be entirely forgotten by the time the end of the year rolls around, which is a crying shame because the game — a spiritual successor to the Baldur's Gate school of RPGs — has been warmly received from gamers and critics alike.
If you're one of those who do like your text-heavy, pause-for-combat RPGs, then you'll be pleased to know that you can pick up the first part of The White March, the expansion for Pillars of Eternity, on Steam now.
It's US$15, although you'll have to pay US$25 if you want instant access to the second part of the expansion when it launches "this winter". Obsidian are based in the United States, so that means the conclusion to The White March should come out by January or February (thank you kindly to @NegativeZero for helping me work through the brain fart I was having at the time of writing).
There is a small chance that Obsidian will push the expansion out in December, although given how stack the release schedule is I wouldn't be surprised if they waited for the clearer air of 2016 instead.