MacRumors.com

Two major instant messaging clients (AIM and Beejive) for the iPhone and iPod Touch were updated tonight with support for Push notifications. Instant messaging was always cited as one of the major reasons the iPhone and iPod Touch needed some form of background processing. Prior to iPhone 3.0, if you were to switch out of these applications, there was no easy way for the applications to notify you of an incoming message.

AIM (Free) - AIM is the official AIM client from AOL. The new version allows you to stay logged in for up to 24 hours and receive notifications through Apple's Push Notification system.

BeejiveIM ($9.99) - Despite its higher price, it has been a very popular instant messaging client with support for multiple protocols (AIM, MSN, Yahoo, GoogleTalk, Facebook, ICQ, Jaber, MySpace). The latest update adds push notification support and other enhancements.

Push notifications require the 3.0 firmware that was released last week. Apple announced today that it has been downloaded over 6 million times since it's release.