what/how to deliver a keynote address speech ( any tips?!!)

hi everyone,

as you can see that I'm already preparing for my User keynote address for the Social networking and eBusiness conference on April 23-24, 2009 at Hotel Intercon.

I will be there as keynote speaker for being a user of social networking sites like Facebook, multiply, friendster and many more.

it will be my first keynote and also my first time to have a talk in a big event.

right now I'm researching on how will I start and what topics should I include in my keynote speech. hmmm.

if you have any tips, advice, suggestion, just post it away.

more about the event - http://socialnetworkphilippines.blogspot.com