The CW has released an official description of the episode “6.10 – Caged Heat“.
which airs Friday, December 3rd, 2010. (Warning: Episode Spoilers ahead!)

MEG’S BACK! — Meg (guest star Rachel Miner) kidnaps Sam (Jared Padalecki) and Dean (Jensen Ackles) and tries to force them to tell her where Crowley (guest star Mark A. Sheppard) is hiding. Sam makes her a deal – they will help her find Crowley if she promises to torture him for information about how to get Sam’s soul back. Castiel (Misha Collins) joins the fight but finds it difficult to work with Meg.

Directed by: Robert Singer
Written by Brett Matthews
Story by Brett Matthews & Jenny Klein

Source: The CW