It might not be quite in-game (instead it's a pop-up window), but XFire works well for communication with others inside or outside the game.
Ello ello, I was just wondering. What are the supported filetypes within' The Matrix's radio? MY theory is it's using the same protocols from your version of Windows Media Player, as the same filetypes from that are carried over. I have seen the radio play .flac, .mp3, .wav, and .m3u. Also, I heard there was a way to communicate to AIM users within The Matrix, is this true?
Matrix uses a unfriendly interface with the Windows media player api.
AIM comms are no longer in the game.