Hi,
came across this FREE tethering software for Nikon cameras:
http://digicamcontrol.com/
Have tried it with my D7000and it works perfectly. Supports DSUSB for bulbmodeand Liveview! and it works!!
Also has an Astro option with some integration with PHD guiding.
I bought ControlMyNikon, but can't get it to use DSUSB despite it saying it does.... Found Digicamcontrol whilst searching for a fix for DSUSB....
No need to go any further....
Apologies if this has been mentioned before.
cheers
Gary