I just looked at Soundcloud, but their introductory pages are so deficient in any real details....

I found that to be a common problem. I found this site which had a guide to music hosting sites, but most of those I looked did not really make it clear what exactly they were offering.

What is needed is recommendations from people who use the various sites.

I was unimpressed with Rapidshare. I followed Suibhne's link and when I tried to connect to his music links, the site seemed to freeze. I checked on my homeplug link and the led's showing activity were constant - ie. no activity, so I closed the page and tried again at which point I got an error message implying that I was overloading the site, so I closed the page again and retried and this time got an error message implying that I was initiating a denial of service attack. There is something wrong there and I am not sure what it is. Most links like that in Suibhne's will take you to a player, but this seemed to take you to a sign up page, so I don't know what was going on. I do know I won't be using Rapidshare.