Christy said that the Charmed Ones wanted to train Billie so they can make her do all the work, but in the episode Malice in Wonderland Billie offered to help them out if they taught her everything they know. So Billie shouldn't act like they used her.
From one shot to another, Phoebe's fingernails either have red polish on them or don't. It is especially obvious when Phoebe's nails are red when she talks to Piper, hears something and storms to the kitchen, and aren't when Phoebe enters the kitchen and finds the little girl.
All the children seen in various clips of Phoebe's dreams and as Piper's grandchildren, they are actually children of most of the crew working on 'Charmed'
Paige mentions Quentin Tarantino as someone she wants to dream about, and in real life, actress Rose McGowan starred in the 2007 film "Grind House" directed by Quentin.
When the girls collapsed after being put to sleep by Billie and Christy, Piper's hand was in between her legs but in a shot shown later on she has it resting on her thigh.
TRIVIA: Billie & Christy's combined powers have advanced to the point that Christy has to only hold on to Billie's hand and channel Billie's Projection power by herself - without Billie's help.
Phoebe: Ok. What did Billie say to you at the club?
Piper: She said something about... I kept blowing her up, and... you know... right about now that seems like a pretty fabulous idea!
Phoebe(about Billie & Christy): Piper, why don't you just freeze them?
Piper: Because it wouldn't have worked.
Phoebe: Okay so it's better to just start a war?
Piper: Oh stop, it was one lousy potion. I just meant to scare them. I wasn't gonna take them out with that!
Phoebe: Take them out? Why don't you say what you really mean? Kill them.
(Piper sighs)Paige(from the other side of room): Girls, be nice!
Paige: Why can't I dream about someone cool like...I don't know... Quentin Tarantino?
A reference to the famous director Quentin Tarantino, known for such films as "Pulp Fiction", "Reservoir Dogs", "Kill Bill, Vol. 1" & "Kill Bill, Vol. 2".
Title: The Jung and the Restless
This is a reference to the daytime soap opera The Young and the Restless. Plus Carl Jung was a Swiss psychiatrist and founder of analytical psychology; widely known for introducing the concepts of archetype, and the collective unconscious.