Very recently at SpeechTEK 2006, Terry Gold demonstrated true remote-based Microsoft Speech Recognition and Unified Messaging quite successfully.
Using a plain old telephone, he logged into Outlook Voice Access back at Gold Systems in Boulder, and used Microsoft Speech recognition to navigate into different areas of Outlook, and perform various tasks, e.g. updating his calendar, sending an e-mail. The demonstration went flawlessly, and Terry notes that remote-based speech recognition will present tremendous opportunities for Microsoft Office Communications Server 2007.
You can read more about Terry's demonstration at SpeechTEK here.