I'm not sure how "instant" you can be using an SMTP server.

Andrew Coates outlines a solution here; it requires the purchase of a third-part chat server.
http://www.civilsolutions.com.au/publications/chat.htm

>A while ago I saw an article in FoxPro Advisor that described using SMTP to build a VFP "chat" function in VFP. I am not able to find the referrence. Anyone remember this one - or have any other suggestions or a direction to head to implement such a feature in a VFP app?
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>Thanks in advance.