I don't think this has been posted before.....
The wipedia article says that IMDB says Tara Strong, the voice actor of Rikku, will also be doing the voice of Penelo........

Voice-overs

Only 5 English language voice actors have been announced as of August 29, 2006. Square Enix is currently working on localizing the game for the U.S. Noted translator Alexander O. Smith has been confirmed to be involved with the English North American localization of the script. Smith had also previously worked on the localization for Vagrant Story. The first English language trailer was shown at E3 in May of 2006. Most of the main characters were shown with their English voices.

It has also been noted by IMDB that Tara Strong will provide the voice of Penelo in the U.S version of the game.
Link

http://en.wikipedia.org/wiki/Final_F...II#Voice-overs

I liked Rikkus voice so i kinda like the idea of Tara Strong doing the voice of Penelo.....but it's kind of weird that they would use her voice in two Final Fantasy's
Tara Strong has done a lot of voice acting and i like a lot of the characters she plays so yeah..............
Heres the Wikipedia article on her
http://en.wikipedia.org/wiki/Tara_Strong