I'm a new learner to FPGAs and CPLDs.As far as I know, it would be much easier to program in VHDL than assembly language since you are using a Xilinx product. If your board has a JTAG programming header or an USB programmer similar to the one that comes with Spartan 3E development board, I can safely recommend Xilinx ISE 8.1i (aka ISE WebPACK). And the best thing is - it's free - both software and tutorials. I haven't yet got a chance to hack all the neat stuffs out of my Spartan 3E development board but I think VHDL is the way to go with FPGAs. By the way, what are you trying to accomplish with your Spartan 3E chip?