[Patrick]

Do you mean something like this?

pawn Код:

CMD:music( playerid, params[] )
{ 
    new 
        AudioLink[90] //change the string value if the link is more than 90 strings
    ;
    if(sscanf(params, "s[90]", AudioLink)) 
        return SendClientMessage(playerid, -1, "/music [URL]");
        
    PlayAudioStreamForPlayer( playerid, AudioLink ); return 1;
}

Or something like this?
http://kiwi6.com/
where you can upload .mp3 files and stream it.