My iChat connection to AIM was dropped, too, but the network problems got worse. After several unsuccessful attempts to get back on iChat, the Mozilla download I was running stopped. I assumed that OS X needed a reboot, but after OS X again couldn't find a network connection, my "Aauggh" joined the other "screaming teenagers" who had been disconnected from AIM. My router had gone down, disabling all the network connections in the workgroup. I had to power down the network and bring the router and modem back up separately and manually.