According to RussianiPhone.ru, the iPhone 2.2.1 beta firmware apparently contains support for both push notifications as well as over-the-air MobileMe syncing with Notes support.
For those of you who don't know what is push notifications, push notifications allow you to receive notifications pertaining to a specific application (e.g. instant messanging) on your mobile device without actually having the entire application running in the background, in the other hand saving battery power and improving performance.
iPhone-users were originally supposed to receive push notifications back in September, but according to an email sent by Steve Jobs, ”We’re running a bit late. We want to get it 100% right the first time.”
So lets hope this rumour is true and we will be able to see Push Notification in the next update.
Update i found a video which will explain on push notifications in more detail.