Can Google TV access windows shared folders on the same network and play files from them? If not is there an APP that provides similar functionality?
I'm no developer but as far as I know you can not do this at the current time. There is only functionallity for DLNA serivces through Windows Media Player. Hopefully third party apps will be created to stream files off the local network in the near future. This is something I would like to see as well.
Grab PS3 Media Server. It's free and it converts videos on the fly. So most MKV HD files will play just fine (if it contains DTS audio for some reason it will default to that and not play audio....I havent found a fix yet), all divx files, some mp4s. I've had a lot of good luck with it and the quality is awesome...even over wifi.
You can download TVmobili DLNA server software which will allow you to share selected folders from your PC or MAC.
My Sony Google TV CAN play .mp3's AND Movies that I have ripped to my windows home server.... it works awesome and much better than streaming with a PS3.