I thought you all that use (and program with) Sphinx might be interested to know that Shodan, the programmer of Sphinx, put up a wiki for the Sphinx community after we cajoled a bit. To show the fruits of that effort, I've written the documentation for the PHP API of Sphinx 0.9.8-r1065 on the wiki. It's a bit more friendly than the comments of sphinxapi.php
http://sphinxsearch.com/wiki/doku.php?id=php_api_docs
Most of the methods are valid for 0.9.7, but honestly, 0.9.7 is so outdated by 0.9.8 there's hardly a comparison. There's a lot of methods added in 0.9.8.
We haven't got around to updating the actual Sphinx documentation to 0.9.8 yet but it's planned.