This package contains some Direct Show filters for Ogg Vorbis and Monkey's Audio. Please use only the playback filters (VorbisFileSource and MonkeysAudioFileSource). These two filters get automatically registered with Media Player, if installed. So you can simply right click and select the "Play with ..." menu item.
There are also info tip extensions registered with the Windows Explorer on Windows 2000 systems (and probably Windows Me, but I have not checked it). If you pause mouse movement over a Vorbis/Monkey's Audio file a tool tip pops up with some information about the file.
There are also other filters in this package, which can only be accessed programatically or via the Filter Graph application from the Platform/DirectX SDK. However I don't recommend using these filters, because they are likely to change in the near future and encoded data may be lost then.
The source is accessible from CVS at the ZoranNT project site. You can simplify the download process by using the DownloadSourceHelper packages.