31 DAYS... and counting...
If you are considering documenting your builds and are not familiar with LDraw, you might want to get familiar with it before NXT is released. I've downloaded and installed it and have begun playing around with it... I wouldn't say it's easy, but it's not exactly difficult either. There are also a LOT of tutorials available (as I'm finding).
One caveat is that there are a LOT of add-ons as well. And many of these add-ons are almost required, not suggested, in order to make some really detailed instructions and/or images.
The easiest way to get started is to download the complete LDraw Installer with all the suggested add-ons built into the Installer. You can download that here.
There's also an Unofficial Parts List you can download here. This list is updated every now and then, so bookmark it.
Finally, there are some tutorial for getting started. Click on the "Tutorials" link on the LDraw.org page (left side, under the References category).