English Cast:

Light Yagami: Brad Swaile
L: Alessandro Juliani
Souichirou Yagami: Chris Brichon
Ryuuk: Brian Drummond
Raye Penbar: Michael Adamthwaite
Aizawa: Trevor Devall
Misa Amane: Shannon Chan-Kent (?)
Rem: Colleen Wheeler
Matsuda: Vincent Tong
Naomi: Tabitha St. Germain

According to a report at Zannen, the voices in the trailers were not the final cast, and final trailer for Death Note should sound better. Other notables, Near and Mello are still being cast,  and there have been 12 dubbed episodes completed so far.

Thanks goes to Kurishojo for sending us this information.

SOURCE: Zannen, Canada