There are various reference designs for the Spartan-3 Starter Kit Board available at the following link.
formatting link
The MicroBlaze Master System does require the Xilinx Embedded Development Kit (EDK), which sells for a suggest US$495 retail price. The MicroBlaze
32-bit RISC core and various IP functions ship with the Xilinx (EDK). The EDK includes both free IP and some evaluation IP of advanced functions.
formatting link
Here are some links regarding MicroBlaze and the associated IP.
MicroBlaze 32-bit RISC Processor Core
formatting link
IP Cores included with the Xilinx EDK
formatting link
If your system needs only a simple processor, the PicoBlaze 8-bit RISC microcontroller core is available as a free reference design. The "Digital Clock PCB Monitor" design for the Spartan-3 Starter Kit uses the PicoBlaze controller.
formatting link
Here are few links related to PicoBlaze.
PicoBlaze 8-bit RISC Microcontroller
formatting link
PicoBlaze User Guide
formatting link
--------------------------------- Steven K. Knapp Applications Manager, Xilinx Inc. General Products Division Spartan-3/II/IIE FPGAs
formatting link
--------------------------------- Spartan-3: Make it Your ASIC