You can register and enrol on a training course at http://www.netezza.com/support/education.aspx

If you have access to the Netezza Admin GUI, the product documentation is installed with it in PDF format.

Once you have a server installed, you can get the documentation that comes with the product.  Interesting reads would be the Database User's guide (DUG) and the System Administrator's Guide (SAG).  The documentation is automatically installed on your desktop if you install the NPS admin utility.

Working on a new revision - with the Twinfin in mind - stay tuned