Death Knights are among the most-changed classes in the first PTR version of patch 3.2, which is not terribly surprising for such a young class. Because of such significant changes, all DKs will receive a free respec.
Blood Strike will scale more from disease (up to 50% per disease), while Frost Strike is receiving significant nerfs: it can now be dodged/blocked/parried, and only gets a 55% bonus from weapon damage, instead of 60%.
On the tanking front, one of our major cooldowns was nerfed, although DKs are still probably the king of tanking CDs (disgustingly powerful new Ardent Defender aside). Icebound Fortitude's CD was doubled to 2 minutes. Veteran of the Third War's Stamina bonus was cut in half, and Toughness was cut by a third.
As for DPS, both Dancing Rune Weapon and Gargoyle were changed to a fixed duration for 60 Runic Power, 12 and 30 seconds respectively, and the Gargoyle now flies closer to the ground so melee can hit it.
Desecration is now a PvP/slight tanking talent (2 points for 25/50% snare, no damage increase), but a new talent called Desolation has taken its place: causes Blood Strikes to increase all damage the death knight deals by 1/2/3/4/5% for 12 seconds.
Speaking of PvP, Lichborne's duration was reduced to 10 seconds, but the cooldown cut to two minutes.
Unholy Blight was completely reworked. It looks like now it makes your Death Coils apply a 10-second DoT equal to 30% of your DC damage, which stacks in a like manner to Ignite and Deep Wounds. So less AoE damage, but more single-target, for the Unholy DPS DK.
Frost got a big new talent to prop up dual-wielding, as the devs were saying they might do. Threat of Thassarian reads: When dual-wielding, your Death Strikes, Obliterates, Plague Strikes, Blood Strikes and Frost Strike have a 30/60/100% chance to also deal damage with your off-hand weapon. Off-hand strikes are roughly one half the effect of the original strike.
That's about the size of it as far as DKs are concerned. As an Unholy DPS player myself, I'm pleased with the changes. Desecration was irritating, and Unholy Blight, while fun on AoE, made the rotation a little complex.
Patch 3.2 will bring about a new 5, 10, and 25 man instance to WoW, and usher in a new 40-man battleground called the Isle of Conquest. WoW.com will have you covered every step of the way, from extensive PTR coverage through the official live release. Check out WoW.com's Guide to Patch 3.2 for all the latest!