Ok, maybe I'm late to the game, but I've found a workaround for the lack of push notification for IMs on the iPhone...
First of all it requres IM+, the paid version, from Shape Services. Right now it is on sale for $7.99 instead of the original $9.99.
You also need unlimited texting, or it could get expensive.
IM+ is also really sweet because it also works with all your IM clients: AOL, Google, MSN, Facebook, MySpace, Yahoo, and Jabber.
First, there are a couple options in IM+ to setup. First, set it to keep you online even when ya close it. I set mine for 3 days. Then set it to email you when you get an IM.
Next set up your email address as [your cell phone number, including area code]@txt.att.net
Now, when you receive an IM, even when the app is closed, you will receive notification via SMS. Then you just pop into IM+ and there's your message, waiting to be replied to....
Labels: iphone, news, sale