Graduation Pics in an auditorium.

Need help! I was asked to take some pics of a small 30 person class tonight as they get their diploma. It's in a school auditorium, low light I'm assuming. I'll be at the foot of the stage.

Any hints on flash technique with my Canon Powershot G2 and 420EX flash? I've never really used the 420EX other than just using program mode and flashing away. I'd like to deliver some decent photographs if I can effieciently work the flash.

Thanks for the help.

Program mode should be fine. Don't try anything new if you have to deliver images. Flash metering can sometimes produce seemingly random results. When you have time, or when yure shooting liesurely, play around with your camera. Practice and react