Did a quick google on this and found alternatives to Nikon's Camera Control Pro 2 (costs $360 according to Nikon's website)
Tethered Shooting can now be free for Nikon users too!
For Windows users,
DIY Photo Bits Camera Control 4.0
For Mac users,
Icarus Camera Control
For the very rare Ubuntu/Linux users,
Also, for the electronic engineers among us, here's the Ultimate Wireless Transmitter Alternative.
PeteTether 1.1 - A Wireless Portable USB Tether
Apparently, this under $100 DIY thingy outperforms Nikon's clunky WT-4a.
I'm gonna give SoFortBild a try tonight.
So if you want to be cautious, stay tuned for an update.