You're missing the point. An iPhone IRC app should be connecting you from a third party server on the internet. Even WITHOUT Push this is necessary because cellular connections are NOT that reliable. Your phone, with its unique identifier, simply synchronises with the server that is holding your actual messages.
Push can be a simple audio notification when someone says your name. OH NO, HOW INTRUSIVE. As intrusive as, oh I dunno, any IRC client on a computer. And just like a computer, any decent app will allow you to turn features on and off. There are plenty of ****** apps in the store at the moment, and of course ****** Push implementation is no exception. If the app is bad, don't buy it. Easy. Quit your bitching.
And on that note... Apple REVIEWS ALL APPS. That means apps that spam crap all the time won't be accepted. This isn't a free market like the Android. Oh wait, they deny apps too if the cell network tells them too

They just don't have a junk filter.
Someone also said "What if Apple pulls the plug?"... the chances of that are about the same as them pulling the plug on the app store. Doesn't happen.
Push is a good solution. Yes, it doesn't suit everything... AirSharing, for example, still needs to have the ability to run in the background. But by releasing Push NOW you prevent a bombardment of ****** apps that expect a constant connection when it's absolutely unnecessary. What they should do is release an API for building 'Services' in a few months, with VERY strict guidelines as to what will be allowed. If it can be done with Push, a service with the same functionality should be denied.
Why do people always do this? No matter what the product is, you all flame without thinking about what you're saying. Just let it be released and learn the culture before starting a war.