The Fluke 1735 Three-Phase Power Logger comes with two different USB options, the first is an external RS232/USB converter, the second is the built in USB interface (starts shipping April 2010).

USB drivers for external RS232/USB interface:
Download USB driver for Vista
Download USB driver for Windows XP

USB driver for built in interface:
Now supports 64 bit operating systems (Vista and Windows 7)
Fluke1735_345_drivers.exe