Once you get this all built and installed, your favourite libsndfile apps should happily support Ogg Vorbis and Speex files (as well as the audio tracks of Ogg Theora files :)
An Ogg-enabled version of libsndfile can be checked out of my arch repository:
tla register-archive http://www.metadecks.org/arch/ tla get conrad@metadecks.org--hack/libsndfile--hack--0 libsndfile--ogg
Ogg support requires:
svn co http://svn.annodex.net/libfishsound/branches/1.0-stable/ libfishsound
These in turn depend on libogg, libvorbis, libvorbisenc, and libspeex. The release versions of all of these as provided by your distribution should be fine.
Ogg Flac support has been developed by Tobias Gehrig, and is pending merge into libfishsound. Patches are available at libfishsound-flac.
Conrad Parker, October 2005