I am trying to make available on my website a voice chat for a small group of people that allows some other means to interact such as text messaging, photo sharing, file sharing, simple drawing and silly games. In other words, something similar to older MSN Messenger, but on the web. Any ideas on what to use?

To clarify, I am looking for suggestions on languages and libraries to use. I want to be able to fully customize it as much as possible because I might want to add other (somewhat interesting) functions later. Low-level programming is fine if required, but platform dependency isn't that much preferred.