BBM Alternative
 

My wife and I travel internationally a fair amount. We have both packed Blackberries and used BBM to communicate with each other. She is stuck with Blackberry because of her employer's requirements. ATT just let me switch to International Blackberry, Smartphone, or iPhone. I have unlimited data on any phone abroad. I thought about jumping to an iPhone (jailbroken). Losing BBM is the one problem.

I've thought about Shape Service's IM client on both phones. What I want is an IM client that will have some sort of push notification that can give my wife a similar experience. Any opinions?

I grew up on AOL Instant Messaging and now AIM and even now decades since I stopped using AOL I still use AIM as its what the majority of my friends still use. They have a decent iPhone client that will do push notifications, as well as a Blackberry client. There are lots of IM aggregaters too for the iPhone that I believe do push as well.

Have a look at WhatsApp. It's available on both Blackberry and iPhone:
http://www.whatsapp.com/