Hi,
You have until the 30th June, so there is no real rush at this precise moment.
As a starter for 10 as it were, go to the Apple ID siteor the iForgot one and make sure all the accounts you have with Apple have recovery emails linked to them and that you have full access.
1) Decide if you are going to Upgrade to Mountain Lion or Mavericks.
If so, get a @icloud ID to use as an AIM valid Screen Name
Note 1.
I did this with my original Apple ID which is based on a dial up email account.
This gave me an @me.com ID in addition and later I also got an @icloud.com which then gave me two AIM valid IDs.
If you had an @mac.com and did it at the start of iCloud then you may potentially have three current valid IDs (although as I said the iCloud issued ones already don't work in iChat 5 or lower) - or you might have linked it since the .Mac days.
2) If you are not going to upgrade your OS (and therefore iChat to the later version of Version 6 or Messages) then get a new AIM registered name.
Note 2
Last time I checked AIM still needed a Recovery email that worked (much like registering with iCloud or any of the earlier services)
Potentially as your @Mac.com name may still work as an Apple email you may be able to use that. (or any iCloud Issued @me.com or @icloud.com).
3) Once you have done either 1) or 2) then you have to create a New Buddy List in the app you are in.
4) You then have to transfer all your Buddies to the new list.
(Select All and Drag them across to the new list (I have done a move of 264 in the past).
5) Inform your Buddies that your Screen Name is about to change.
6) Obviously at the same time you will have @Mac.com and @me.com Buddies also changing their Screen Names.
bobbybray wrote:-
Also, if some of my ichat contacts are on my @mac.com acct, how do I transfer them as at the moment, I am using messages but it has my @me AIM acct, my @mac AIM acct and my @me iMessage acct. I would prefer to just log in with one for all!!
At this point you will be able to move somewhat towards this.
Lets say you end up using just the @iCloud ID part of your Apple ID.
This can be used to Login to iMessages.
It can also be used to Login to AIM.
What they will not do is one Login to both services.
(neither will a Google Mail ID as an Apple ID which can be used as an iMessages and Google login)
I have @mac.com names that were originally Trials during the .Mac service.
I have some that were registered on the "iChat Registration page" which was a revamped @mac.com registration page during MobileMe (they never worked as email accounts).
10:10 pm Thursday; April 24, 2014
iMac 2.5Ghz i5 2011 (Mavericks 10.9)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
Couple of iPhones and an iPad