The folks at FreeRangeFactory.org released an open source book on the VHDL language called Free Range VHDL.
It’s a good book for being freely available, but it surely lacks the techniques required for implementing a VHDL design on a real FPGA. I will hopefully be creating my own tutorial on things I’ve learned in FPGA development and testing.
The best book that I’ve found so far on VHDL simulation and implementation is surely, “VHDL for Logic Synthesis.”
This book is great because it goes over the final details of how the VHDL simulators work and how your VHDL programming style will affect your hardware implementation. I found this book by chance at my university’s library.
You can download Xilinx’s ISE development environment for free at:
They always change their licensing, but you should be able to compile and synthesize designs for some of their older FPGAs. The newer FPGAs and the coolest VHDL cores that Xilinx provides come at a licensing cost, of course. However, you can always create your own cool cores!
While Xilinx ISE has an integrated VHDL simulator, it is slow and lacking some features of the features that are in ModelSim. If you are a student (but who isn’t really?) you can download ModelSim’s student edition.
The student edition isn’t optimized for large-scale VHDL designs, but you probably won’t run into this barrier unless you are trying to simulate an ARM processor.