How awesome it would be if Apple included a native messenger that included AOL, MSN, FB?
Now, I also put some thought into this idea.
Theres two possibilities I've came up with.
A) Messages App could be a universal 'messenger' sort-to-speak.
And contact's in your Address Book would have an "AIM," FB," or "MSN" spot like there is now for just AIM.
When you compose a new mesg, you can choose how to send your mesg. So instead of only having the option to chose their email, or phone number. You can also send via IM service.
But its tricky, how would you be 'logged' in? Well, maybe there can be a option pane in the settings menu that allows you to connect to your IM client, and download your contacts into your Address Book, or not import your contacts and you pick who to send to.
So lets say they aren't online, or available. I haven't yet figured that one out though
B) Apple makes separate integrated Apps that interact flawlessly with the IM client.
Both of these idea's probably won't happen through Apple. But, I'd like to throw the idea out there for a Homebrewer. Obviously, you'd need a jailbreak to accomplish this.
Ummm have you looked at any of the IM apps in the store. Or even facebook can sync with your addressbook. With BeeJive you can link your buddies from IM networks to your addressbook too.