If so, is there any online document describing how to install/configure it? Thanks.
I don't know if it is available as an out of the box server you can configure and use, but I believe the APIs are there for someone to build a Vxml browser.
Lync VoiceXML Sample (QuickStart) - http://msdn.microsoft.com/en-us/library/gg448288.aspx
VoiceXML Support in UCMA 3.0 Core - http://msdn.microsoft.com/en-us/library/gg448321.aspx