I haven't seen anything one way or another, but I do know that every time a user makes a clean Vista installation , we know that this user (for at least a few minutes) will have a clear machine. Also, it is apparenly much more difficult to install downloaded programs (requires the admin password) that might make people think twice before actually allowing the thing to install.
Zango is entirely dependant on tricking people into thinking they are download a video to watch, and not a toolbar or popup generator. When people see that they need the admin password to watch a video, they might think twice.
Further, this may stop children from downloading and installing the toolbar without parental permission.
I think vista will help. I have not seen anything that shows how it handles the install and continued annoyance that is Zango and it's asterixware peers.