Instant Messenger Program

Operate a membership site using ProfileManager by Interolgy and PHPBB Board. Need an Instant Messenger for the member's area of the site that does the following: 1.? ? ? ? When members login to the Member's Area they are auto logged into the IM - this can be done via either the Profile Manager login or the PHPBB as they are integrated. 2.? ? ? ? No windows/screens open but they show available for IM 3.? ? ? ? From a list of who is online (which I have already generated) - another member can click on a members screen name and a chat invitation is sent to the member they clicked on. 4.? ? ? ? If the second member accepts the chat invitation - then both members IM opens and they can IM back and forth. 5.? ? ? If second member declines - a screen appear saying the IM was declined. This would be a 121 chat situation and I do have PHP121 installed on the site if you can modify that to achieve the above.