FFT in VHDL (or Verilog) Tutorial

Hello,

Can someone point me to simple implementation of FFT in VHDL(or Verilog) with testbench and good step-by-step description. I have implementation from Xilinx (which I will eventually use for hardware implementation), but I find it rather confusing (lack of vhdl experience). Algorithm used, # of points, Radix#, bit precision do not matter, as I'm looking for tutorial-like implementation. The best example of what I'm looking for is (found using google)

Thanks.