Adding an online conversation option

Hi everyone,
if I have a website with registered users and i want to create a feature which will let the online users talk with each other through the website, by choosing whom they want to talk with (of course if he is available and online).
how can i add create/add this feature to my web site ? which tool should i use to make the conversation and which tool to make the list of "who is online and avalible"

Thank you !!

 

look for shoutbox script in google

 

in what program language can i built a one of my own ?

 

I've done it in PHP.

 

You can hire a php expert who can write the codes for you. There are freelance sites that you can hire that can do the job for a low price.
But there are also CMS Content management systems that are free that offer a shoutbox option. All you need to do is to activate the option on the admin panel.

 

You can search for a chat widget for it.