The NetFPGA-10G code base is covered under version 2.1 of the GNU LGPL. Xilinx IP, however, is an exception to this and covered under Xilinx licenses. The following is information on how to obtain a license for various Xilinx IP:
Anybody can get an evaluation license for free which allows the end-user to simulate the system, however bitstream generation is limited. For a full hardware license, academic end-users can request a donation through the Xilinx University Program. Other end-users have to purchase a "SignOnce" license. Evaluation license or the full license can get obtained through the links on the 10G MAC page. To obtain a free full hardware license for academic end-users, please visit the Xilinx University Program and submit a donation request for the following part number: EF-DI-10GEMAC-SITE.
This webpage explains how to install the license.
Xilinx XAUI core is included in Xilinx ISE installation at no additional charge. The "make cores" script handles the core generation automatically. Please refer to "Installation" section of Getting Started Guide
Xilinx EDK cores are included in Xilinx ISE installation at no additional charge. The "make cores" script copies those cores to NetFPGA-10G library automatically. Please refer to "Installation" section of Getting Started Guide.