Get the hardware and download the software:
The DE5 board can be obtained from the Altera Corporation. The borads are sold for a discounted price when used for educational purposes. They are also available for commercial use, but pricing is higher.
Altera Quartus II is the primary FPGA development tool to create the reference design as well as Nios II embedded processor. Download the ModelSim-Altera design suite in Altera Download Center.
Jungo WinDriver is used to create the PCI express driver for Windows systems, and is necessary for interfacing with the DE5 NetFPGA. Download WinDriver at Jungo official site.
Microsoft Visual Studio 2010 provides the development environment to build the software in this project. A free trail version can be downloaded from Microsoft.
Download the DE5 packet generator/reference router design from the download page.
Now you are ready to go!
Follow the user guides to go through the sample designs, and develop your own design right now.