A Movie Very Similiar To This One...?

Pretty Persuasion.
Starring Evan Rachel Wood.

"In Beverly Hills, the fifteen years old evil manipulative aspirant actress Kimberly Joyce (Evan Rachel Wood) convinces her friends Randa (Adi Schnall) and Brittany (Elisabeth Harnois) to falsely accuse their Literature and Arts teacher of sexual harassment. She manipulates also the lesbian journalist Emily Klein (Jane Krakowski), who is covering the case, to support their cause in the trial, which leads the group to a tragic and surprising conclusion."

It has the lesbian sub-plot and everything.

Cruel Intentions
Tart, which also has Dominique Swain
Pretty Persuasion was a great pick too
maybe Thirteen? it's a younger scene, but it has the whole "goodgirl goes bad with popularity and drugs and then is outcast" thing

The In Crowd

Thirteen?

Same general good girl gone wild child kind of thing. It's an independent movie as well.

"Don't ever tell anybody anything. If you do, you'll start missing everybody."

the in crowd is pretty close

Jawbreaker