I have a TV and an AV-receiver which are DLNA-capable and which are attached to my home network together with a Windows 7 desktop and a MBP running OSX Lion. I can access audio from both computers using a DLNA-server software on either computer (built in DLNA-server on Windows, PS3Media Server on OSX). So far this setup works fine and i can browse through my audio on the receiver.
However the TV and the receiver also act as UPNP/DLNA media renderer. For example I can use my phone to display photos on the TV (e.g. using the Twonky app on Android). On Windows, I can use Windows Media Player to play audio on either device without having to touch any remote control. I select the track/playlist I want to listen to, right click select "Play on" (maybe not the exact wording as my Windows is German) and select one of the two devices (e.g. the AVR for audio). Now I'm looking for the same for OSX. Either an application/media player which can use a media renderer as output device or an app which redirects all audio output to such a device. Does anybody know such software?