Have you ever taken a course in digital hardware? If not you should probably read a little bit about that before doing anything else. Unfortunately I don't really know of good books in English in this area because we are mainly teaching these subjects in Swedish.
Once you know a little bit about digital hardware you can draw a little schematic and translate it into VHDL or Verilog. The learning curve of VHDL and Verilog is actually quite low _if_ you know what hardware your are planning to design.
May I ask why you are interested in learning about VHDL or Verilog? Do you have a particular project in mind? Hobby or professional interest?