See:
http://www.neatvideo.com/nvforum/viewtopic.php?t=372
"Neat Video for Sony Vegas Pro 64-bit
The first 64-bit version of Neat Video plug-in for Sony Vegas Pro 64-bit is available!
ABSoft is pleased to announce the release of the first version of Neat Video plug-in for Sony Vegas Pro 64-bit.
Advanced noise reduction features originally introduced in the Neat Video plug-in for the 32-bit versions of Sony Vegas are now also directly available in the 64-bit versions of Sony Vegas Pro: 9 and 8.1 (64-bit)
Please visit the Neat Video website for more details.
If you did not use Neat Video before please try Demo editions of Neat Video plug-ins for After Effects (Win, Mac), Premiere Pro (Win, Mac), Premiere Elements (Win), Final Cut (Mac), VirtualDub, Sony Vegas, Pinnacle Studio."
Jøran Toresen