It discusses all Rogues specs but there is a summary of the basics of Assassination.
[square brackets added by me]
Glyphs: Mutilate, Backstab, and Rupture.
Opener: [Pre-pot/stealth macro]->Garrote->Rupture->[Mutilate - [if no Ruthlessness proc]]->SnD->Vendetta->Mutx2->CB Envenom
Rotation: [Obviously have SND up]. Rupture if its down, Envenom otherwise. [Above 35%:] While Mutilating, use 4+ finishers. [Below 35%:] When Backstabbing, 4+ and 5 give very similar results, but the latter appears to be slightly superior for most gear sets. [Set up a Powa Aura to ping at you when your target reaches less then 35% health].
Poisons: Instant MH, Deadly OH, [DP on thrown for adds that dont die in less than about 10 seconds, otherwise IP]
Stats: Agi (gem Agi everywhere unless you have to gem a yellow or purple to get a 20+ socket bonus) > Hit to 1332 with 2/3Precision > Mastery > Haste > Expertise.