Help with my Afflic PvP :S

Hello everyone, first of all, forgive me for my English.

I am playing with my first warlock in WotLK, and I chose Affliction as my main.I watched some Affliction videos where players use Althor's Abacus. Does this trinket work, is it viable?
I also have doubts regarding Spell Pen. Doesn't Affliction need this since it uses Curse of the Elements?
Another question is Haste. Is 900 a good haste in pvp? Should I use Spell Power gems after reaching that much haste?

Thank you for your attention, guys!

It's complicated...Message me on Icecrown alliance anytime and I can answer all your questions.

-Ingurgitate