I don't receive push notifications on my iPhone 3G 3.0. I am sure that push notifications is on for all apps. I don't have a sim card and i am running my iPhone in airplane mode with WiFi on?
If you are running your iPhone in Airplane Mode you will not receive anything. You won't get phone calls, emails, texts, etc. If you want to get Push Notifications you need to take it out of Airplane Mode, WiFi has nothing to do with it so it doesn't matter if that's on or off.