We offer progressive streaming, meaning that you can upload the file to our servers, and then link to it. When a visitor accesses that file, they can then stream it to their computer, or download it.
We do not provide a dedicated streaming server, so you won't be able to run applications like ShoutCast from the servers, but you can upload your content, link to it, and allow visitors to view/hear it this way.
Additionally, since we offer progressive streaming, users that are behind firewalls, which could prevent them from listening to streams from a dedicated streaming server, are able to listen to the content as well, since the stream would be going through port 80 (standard port for http traffic).
Also, you can embed a media player directly into your site to play the content. For information on how to do this (and a generator to show you how to do this as well) check out http://cit.ucsf.edu/embedmedia/step1.php
Hope that helps!