"Characters from the European server can be cloned and moved without their possessions 3 months after the American launch. Certain restrictions and charges will apply, to be announced at a later date."
The only way to play on the US server from launch is to buy the American Darkfall client. Tasos later added that American players currently on the European server would not need to buy the new client in order to transfer over when the time comes, to help the US early adopters -- any others jumping ship will need to purchase the US version of the game.
In addition to this, during the first week of July players can expect a free expansion to roll out, which will include new content and updates to PvE and PvP. A new website is also in the works, with forums that the public will be able to read, but only Darkfall subscribers will be able to post to.