PHP Voice (formerly known as PHP VXML) contain four classes that assist in developing voice application using PHP. It supports Speech Synthesis Markup Language 1.0, Speech Recognition Grammar Specification 1.0, Voice Browser Call Control: CCXML 1.0, and Voice Extensible Markup Language (VoiceXML) 2.0.
freshmeat.net: Project details for PHP Voice
There amy be something here, but I’m not sure. I guess I’ll need to grab the code and have look:)