(Not 100% sure if this works) And is intended for quick levelers.
This just takes advantage of Blizzard's Recruit-a-Friend Promo.
1. Link another account using the recruit-a-friend method to the account you want to roll a death knight on.
2.
Start the Recruit-a-friend within 90 days of the release of Wrath.
3. Create a level 60 character on the secondary account. Congratulations! You now have the ability to give 30 levels to characters 59 and under to your death knight account.
4. On Day of release give your death knight 5 levels, and do whatever you please with the other 25.
*Tip* Great idea for those of you that want to be the first Death Knight to hit 80 on your server. Buy 2 months gametime on the alternative account, and you can rock a lame A$$ zevrah on your death knight too.
If you want to dual box, grab quests on another character on your death knight account, and just put it in a party and on follow for 3X XP.
Warning: I'm not exactly positive if this promo will still be around near the release of Wrath.
Hope some of you find this info helpful :P.