I'm hoping that the AIM and Google Talk integration makes its way in to the messages app in iOS 6.
This is all, of course, a very logical progression and why I have said that the 'personal computer' is dying. Within 10 years, devices that we use will just be devices, front ends to access our information stored in a central location. Now, not EVERYTHING will be like this. But I'll go out on a limb and say the ultra vast majority of computer usage will be.
It's the future.
Putting AIM or gTalk into iOS is probably not going to happen. Think about it, Lion and Mountain Lion users as well as iOS 5 and up users will be able to message each other with Apple's own cross-device messaging service. If someone doesn't fall into that category, I reckon Apple would rather that they do so than to give them a way to avoid it.*
*They want them to buy newer Macs or a Mac period, or to switch to an iPhone.
