I have my music up on lots of sites, main ones are soundclick, reverbnation, and acidplanet. These are all free sites. I have not checked out soundcloud yet, but have some friends over there, so I'll probably get to it at some point.

The advantage of the music sites as stated above is that people will hear your music without you having to do anything, I've sold a few CD's that way, plus met many new musician friends. I've done a few tunes with a great keyboard player that I met on acidplanet, a Canadian now living in Costa Rica. Lots of fun! All of the sites I am on are genre specific, so someone looking for blues will find me.

I also have my own website. I don't actually host music there because I have bandwidth limitations, but I do have an embedded player that is linked to reverbnation, so best of both worlds.