php IM advice

Hi,

I am writing to ask if anyone could let me know of any tutorials...

I want to make an add-on for my site. What I want to do is add an
instant messanger feature, where members can IM each other.

Preferably, I want to implement this without adding a database table.
I hope to use a combination of both PHP & Javascript. Is this a
realistic approach?

I have looked into this and can't find much information on it.
If anybody has ever done such a feature for their site and has any
articles/tutorials.. on this subject i'd aprechiate it if they could
pass them on. Or also any opinions.

Thanks in advance,
Mikey

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