I stumbled upon following FPGA Tutorial while surfing the web. It is great for beginners, who don’t know what FPGAs are. This Tutorial covers basic concepts of PLDs,CPLDs and FPGAs. It then gives overview of internal architecture of FPGA. Tutorial also gives overview about design considerations, use of Xilinx tools. In short it covers all basics of FPGAs based design flow using Xilinx FPGAs and software tools.