This guide tell how-to install Xilinx EDK under Ubuntu 9.10, using an 30-days evaluation license acquired at http://www.xilinx.com/ise_eval/index.htm.
Follow the download link at the above URL, and download the EDK package, which is roughly 1GB and untar it:
mkdir edk
cd edk
tar -cvf Xilinx_11.1_EDK_SFD.tar
cd Xilinx_11.1_EDK_SFD
sudo ./xsetup
You do not need to use sudo, but if all users on the [...]

The Avnet / Xilinx Spartan-3A Evaluation Kit is a $49 FPGA kit from Avnet, with a XC3S400A Spartan-3A FPGA, and a number of simple peripherals:

Xilinx XC3S400A-4FTG256C Spartan-3A FPGA
Four LEDs
Four CapSense™ switches
I2C temperature sensor
Two 6-pin expansion headers
20 x 2, 0.1-inch user I/O header
32 Mb Spansion® MirrorBit® NOR GL Parallel Flash
128 Mb Spansion MirrorBit SPI FL Serial [...]

This is a short how to install Xilinx ISE Webpack 11.1 / 11.3 under Ubuntu 9.10. Start by downloading the installation files from “Xilinx Download“. The file is 2.67 GB, and Xilinx requires you to have a free account in order to download the file.