Ask HN: How to create a buzz for an iphone app

I will be releasing my iphone app as soon as it is approved by Apple. How and when do you guys think I should release it to the world. From the statistics point of view, most of the apps are downloaded on the weekends, so I am gonna target one of the weekends for the release, but do I need to create any buzz around it before the release or should I just put it live and then do the marketing. How did you guys handle the release of your apps?

Thanks