It seems most of the voice files for Icecrown bosses are in the latest PTR build (nothing from the Lich King fight, from what I can tell, though). There's no way I could upload them all, but here's some samples You can check the rest out yourself by getting an MPQ-extractor program.
Warning, spoilers
The Deathbringer horde intro1: http://www.mediafire.com/?2mnznanniyu
The Deathringer horde intro 2: http://www.mediafire.com/?z4n0qtn2t32
Putricide aggro: http://www.mediafire.com/?2nyzyojzz5n
Queen Lanathel intro: http://www.mediafire.com/?hjmwkd5mmc3
Marrowgar aggro: http://www.mediafire.com/?o3nunxmy25z
Edit: Here's Rotface and Festergut, they're awesome!
http://www.mediafire.com/file/4zu3mh..._Berserk01.wav
http://www.mediafire.com/file/ginjim...Precious01.wav
http://www.mediafire.com/file/qjowjy...ut_Aggro01.wav
http://www.mediafire.com/file/xqzkgw...t_Beserk01.wav
http://www.mediafire.com/file/izklmd...faceDies01.wav
Festergut reminds me of the gumbys from Monty Python's Flying Circus...