Most on these pages based on the BASYS

From the homepages of XiLinx can the free  WebPack  xx.x  (current version) be found and downloaded.

You must make an registration in order to get access - no problem - free and no spam.
Please note that you must download - the latest update as well.

This package sufficient for most examples (99%) at these pages.

The ModelSim Xilinx Edition-III a separate program which can be used together the ISE in order to simulate (VHDL) Components.
It requires a license file - but the starter version free to use (but a bit limited as well)

 The Digilent Adept Suite a must in order to use the USB cable for programming.