iChat Icon   Other people can't chat with me

You can use iChat AV to communicate with people who use Mac.com or AIM screen names. You cannot chat with people using other instant message services.

Make sure your status is Available and that you're logged in to AIM. Also, check the Privacy pane of iChat Preferences to make sure you haven't blocked the other person.

If your friends are using older versions of the AIM software, they might need to get a newer version in order to send messages to your Mac.com screen name or to see when you're online.