Which is the best chat system for an online business?

Hi,
I am urgently looking for a chat system so that I can chat with my partners using a microphone . (group voice chat)
Something which can also show text on screen what the person speaks! (if possible)
We dont need video though..
Is there any system which can store messages as text on the screen if the person is not available for chatting?
Any help would be appreciated,
Thanks guys.

See original post by bombermann