Play music from PC on Android
One option would be something like the VLC app. You actually don't even need the music to be on a shared drive for that one to work, you just need VLC installed on the PC and a wifi LAN to share (or 3G and some network security know-how).

There are also some third-party apps that are designed specifically for the streaming aspect of VLC, without the local playback features, such as VLC Streamer.