http://lolip.hp.infoseek.co.jp/#050626 (warning, Japanese)
Edit: cleaned this up a bit. My command of the Japanese language is poor, but I’m pretty sure this is all correct.
Shirou Emiya - Noriaki Sugiyama
Saber - Ayako Kawasumi
Rin Tousaka - Kana Ueda
Sakura Matou - Noriko Shitaya
Archer - Jun’ichi Suwabe
Fuji-nee - Miki Itou
Kirei Kotomine - Jouji Nakata
This means not just the leads from Marimite (Kana Ueda and Miki Itou are Yumi and Sachiko) but both the leads from Kannaduki no Miko are present. I’m not complaining about that at all. Assuming that the third entry (first two are staff) is Shirou (and that’s a fair assumption)… he’s being voiced by our wonderful friend Sasuke the Whiney Angst-Ninja. I personally hate this guy’s voice, and this is going to be a major downer for me even given the rest of the cast.
EDIT: I just noticed there’s a larger cast list lower down, and I’ve added what I can from that.
EDIT: again — that second list was apparently made up. 
A couple you’ve missed:
Kotomine Kirei: Nakata George (Giroro in “Keroro Gunsou”)
Archer: Suwabe Junichi (Sting Oakley in “Gundam SEED Destiny”)
Archer wasn’t on that list though.
I thought that Jouji Nakata was probably Kotomine, but I couldn’t quite read it.
Needs more Rider. ;_;
Other than that, awesome.
This is the -official- casting so far:
Shirou Emiya: Noriaki Sugiyama
Archer: Junichi Suwabe
Saber: Ayako Kawasumi
Rin Tosaka: Kana Ueda
Sakura Matou: Noriko Shitaya
Fujimura: Miki Itou
Kirei Kotomine: Jouji Nakata
What you saw further down on Lolipuni were the results of the poll he did asking his visitors who they think should voice who.
Well, there you go.
Wasted effort.
For posterity’s sake, here’s the cast list with the bulk of the ‘fake’ ones added in:
Shirou Emiya - Noriaki Sugiyama
Saber - Ayako Kawasumi
Rin Tousaka - Kana Ueda
Sakura Matou - Noriko Shitaya
Archer - Jun’ichi Suwabe
Fuji-nee - Miki Itou
Caster - Kikuko Inoue
Gilgamesh - Hikaru Midorikawa
Berserker - Tesshô Genda
Lancer - Shinichiro Miki
Rider - Yuu Asakawa
Kirei Kotomine - Jouji Nakata
Issei Ryudou - Toshiyuki Morikawa
Shinji Matou - Hiro Yuuki
Ayako Mitsuzuri - Tomoko Kawakami
Yukika Saegusa - Mariko Kouda
Kane Himuro - Yuki Matsuoka
Kaede Makidera - Chieko Higuchi
Leysritt, Sella - Aramari (Mariko Arai)
Most recent rumours place Atsuko Tanaka as Rider and Naoko Matsui as Caster, with Kenji Kawai providing the musical score. But given the source I’m quoting (some Fate fan-forum that seems to have gotten ahold of some details regarding the series’ trailer), I’d suggest taking this with a grain of salt for the moment.