Here's the Poison Watch SCT mod, created by Myana.
Uses SCT to alert the rogue to poison-based events:
* Alerts you when your target is ready for Mutilate (poisoned or stung)
* Alerts you if your target is immune to poisons (most elementals)
* (Future) Alerts you when your target is ready for Envenom (coming for The Burning Crusade)
Style, color, and verbosity of events can be configured through a GUI. Audible alerts are also available.