iChat uses the AIM network so to talk to people without iChat
they will need to be on the AIM network. (See links below) .
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ichat cost $29.00 to buy!!
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Apple does not make iChat for iPad. But if you have an iPad 2 or
newer, you can use FaceTime which is very similar to iChat.
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"You cannot use ichat for Windows. Ichat is used with Mac, but
you can use AIM with Windows and comunicate with Ichat on Mac. You
will also need internet."