Free online music sites.

Been using these while playing PSO recently (Caused myself some lag doing it). I started by using Youtube and just play videos of songs I like, but that didn't work well had to keep going to the browser to start the next video (I know there is a play list thing on Youtube but I didn't look to see how to use it). Then googled and found a few that play free music but its just tributes of well known bands not the actual bands. I tried a site called Jango it had bands and has an interesting idea of introducing you to other things with what seems like a random play list, I tried signing up to see if I could control the play list but I can't, I did come across a few things that I didn't like and so would need to go to the website to change it ingame. I've just tried a site called Grooveshark which lets you set your own play list, it had the best selection of music from a band that I searched for of all the sites, you need to sign up to set play lists, I've not tried it yet so I don't know if you have to pay. I know you need to to remove the adverts (So far they seem to just be on the side of the page and don't get in the way of the music). Does lag PSO a bit sometimes.

http://listen.grooveshark.com

http://www.jango.com/

lastfm - you basically download a player and from you training it what songs you like it makes you radio station and plays stuff you like or it thinks you'll like
if i recall correct live365 works a similar deal

alternativelly any internet radio station you just tune in and they stream the music to you

think is like you say these things use up both the computer resource plus the internet bandwidth, much better to just dump loads of tunes you like in a folder on your pc then direct your music player to use that folder as the playlist that way you may be using computer resource but your not encroaching on your bandwidth and connection stability