If you use the Xilinx FPGA tools (or you’d like to) you may have noticed that Xilinx has an “education” link on their home page. Of course, the main purpose of this link is to sell you fairly pricey instructor-led training (actually, it is pretty reasonable for this kind of class, but more than most of us will pony up out of our own pockets).
However, there are several of the shorter classes available online for free. You do have to register, but the price is free. Some pretty good classes on the Xilinx-specific tools. Don’t expect the Verilog, VHDL, or even the “designing with FPGA” classes for free, but there are titles regarding usage of constraints, basic FPGA architecture, and several other interesting topics.
Check out . It isn’t really clear that some of the classes are free until you “drill down a bit,” so be sure to explore.