Streaming Audio

Hey Guys,
I have been asked by a client to stream 4 separate streams of audio at an event they are doing later this month. I have had a quick look on line however I wanted to ask on here if you knew of any good services that I could use?

Each stream needs to have its own dedicated link that they can send out to people, I was thinking of using x4 Web Presenters, however I would need 4 Machines to do this.

Any advice would be appreciated.

Also you would need to add video to it.. Because the Webpresenter is a video streamer.. Not a audio only unit...

What's the audio sources? Is it just analogue audio coming from an audio mixer? Is there any video for those audio too?

If there isn't video, I think you might not possibly even need to use a web presenter but stream your event like a radio broadcast?