Social media for me. My tumblr and twitter are both pretty music-centric and when other people mention new bands I haven't heard of I try to check them out!
I use radio. Any radio, whether it's iTunes au old school tune-in stuff. Whenever I hear a song I like, I write the name of the song/artist. wewe find a lot of good stuff to be honest.
au wewe just ask your Marafiki what they're listening to. XD