I have updated the Ventrilo Module download for J15.  I have tested the install on a few different 1.5x installations and it seems to work.  If anyone is having problems, please contact me via PM with some contact information so that we may go voice and determine what is happening.

I think I answered this in another post, but I am not positive.  Joomla has a problem with an ANSI character that I added to the XML install.  I have fixed this in the current version on the site.

To get this working, please download the file again.

To answer the actual question in the post, no -- it is not J15 Native.

I apologize if this comes out poorly, but I personally am not too impressed with Joomla and really only write with Mambo in mind.  I attempt to the best of my ability to keep things working for Joomla but do not really want to delve into the J15 native changes.  I am looking forward to the new directions Mambo is taking and am anxious for the 5.0 release.