http://flac.sourceforge.net/download.html
Adamadcap - go here for what you need for flac
http://flac.sourceforge.net/download.html
Also when you install flac it should install plugins that allow winamp to play files and also the nero plugin for burning straight to audio cd.
Otherwise use the flac program to decode to wave and then do whatever you normally do with wave files.
http://tlh.easytree.org/
and go here for the same for SHN
http://tlh.easytree.org/
You can also use mkwACT to decode .shn to .wav,
and a WinAmp plugin called ShnAmp to play them
(assuming you have WinAmp of course!).
There's also a Nero plugin which allows you to
burn .shn directly to audio CD
Enjoy