Update: See Charice perform Louder http://youtu.be/fNH6afE5WLIShe also performed Before it Explodes, Pyramid Iyaz, and One Day with Chaster Vanessa
After first reading about it in Charicemania.com (where they also have a "radio request must-read"), I quickly searched in YouTube for her performance in the same event last year. Below is a playlist of the videos courtesy of SideburnerSol and uploaded by ChariceTVCrew.
Reading the article by LAfan posted in Charicemania.com perfectly complements these videos.
We can expect Charice to sing "Louder" live at the event since 98.5 KLUC is promoting it on their site: New Music From GLEE Star Charice
Read the details of the End of Block Summer Party 2011 below.