Deadliest Warrior Season 2 Episode 8 (Deadliest Warrior s02e08) with title “Persian Immortal vs. Celt” airs Tuesday, June 15th 2010 at 10:00 pm via Spike TV Network.
Here is summary for Deadliest Warrior Season 2 Episode 8 :

A European clansman from the Iron Age takes on a 6th-century B.C. warrior in this bout between a Celt and a Persian Immortal featuring weapons such as clubs, swords and battle-axes.

Few hours after original series aired on TV, online streaming video for Deadliest Warrior Season 2 Episode 8 usually available on Net and of course, if video available, as soon as possible will show you where you can watch this episode for free.