Here's a set of voice lines that were done by IMShadow, the voice of Brutalight Sparcake. She did very will on voicing as Twilight, and I made a voice pack that includes battle quotes, special quotes, and domination quotes.

Princess Twilight Sparkle Voice Pack: http://www.mediafire.com/download/q5p6rjcqwhp049q/Princess+Twilight+Sparkle+Voice+Pack+by+IMShadow007.zip

IMShadow007:
http://www.youtube.com/user/IMShadow007

MLP by Hasbro