Yes, it is true. Not only is Trine 2 finally available in the Steam store for pre-order, but if you buy now you also get access to the beta.
So basically the tutorial stages and the first stage, complete with online multiplayer goodness available right now. Nice.
We here at Frozenbyte will also be joining in for online sessions in the coming weeks and will let you guys now about that on our twitter account.
So be sure to follow us there also if you want in on the action with the developers