The World of Warcraft website has been updated with the Public Test Realm notes for patch 3.0.8, with massive changes on the way for the hordes of recently-created Death Knights.
While there are indeed a great deal of tweaks coming for the game's first hero class, the changes certainly don't represent the massive nerf that players in general chat seem to think is in order. If anything the changes mainly serve to balance out the various Death Knight builds, rather than tone down power across the board. They've traded off some of the bonus damage from Rune Strike in favour of more threat, reduced the duration of a few abilities, but for the most part the changes are positive, including the best change of all - Death Knights will be able to be created on any server, not just the one your level 55+ character resides on.
Other big changes in the patch include the removal of racial restrictions from mounts (Tauren chocobo time!) and the fact that any aggro-inducing abilities will now tap monsters, meaning no more dotting a mob only to have it yanked away before the first tick. Hit up the link for the full patch notes.