Updated to 10.7.2 yesterday for iCloud, now I cannot get my iChat to connect. Anyone else having this problem?
If you are having problems signing in with AIM on iChat go into iChat Preferences, click the Accounts tab, click the AIM account on the left hand side then click the Server Settings tab to the right. Uncheck Use SSL and try signing in again, should work fine after doing that.
I just spoke with Apple Support and was given a fix that worked for me. The rep instructed me to do a P-RAM reset, which apparently clears out the cache on the video card. To perform this operation:
1) Power down the computer with the power adaptor connected;
2) Simultaneously depress the Option, Command, P and R keys, as well as the Power button;
3) Keep all five depressed until you hear the SECOND startup sound (the rep calls it a "chime"), then release;
4) When the computer finishes booting, you can open iChat.
My very uneducated guess is that something about the upgrade to 10.7.2 or the installation of iCloud fills up the cache. This rep was able to verify that others have reported this issue online, but he had been furnished no guidance from Support, and he just solved this on his own on the fly, first try. I like Apple products for many reasons, but being able to receive this quality of support may be among the most important to me, especially after dealing with the poorly trained and ill-qualified support personnel virtually all other consumer companies generally employ these days.