Update 9/2/11: Aaand now with the latest 0.4.2.36 update, Honeycomb support is official.
A short while ago, the Google Voice app received an update that brought about a few bug fixes. Almost immediately we began hearing rumors that a Honeycomb interface may have been incorporated into this build. A quick search of the Market revealed that it's not officially supported just yet, so I pulled the apk from my phone and sideloaded it onto my Tab 10.1. Here is the result:
As you can see, the settings menu moved from its previous location in the navbar to the upper right-hand corner -- the typical place for the settings menu of Honeycomb-optimized apps.