the best source for music is youtube so i just simply download on that page and convert it to a music format
I use rapidshare, torrents, limewire, etc... any source of music download will do! Then I put it on my music blog.
Don't use limewire. If you're going to use P2P like that, at least use frostwire. Same people, more security, less viruses, more results usually. I'd use torrents.