>>40
The Z reference manual:
http://spivey.oriel.ox.ac.uk/~mike/zrm/
The case study approach book:
http://www.zuser.org/zbook/
"Using Z":
http://www.usingz.com/
The Z user group's holy crapload of mostly useless linkage:
http://www.zuser.org/z/
LaTeX stylesheet for laying out Z schemas (get the latex2e version):
http://www.itee.uq.edu.au/~smith/latex.html
It's a good idea to practice first on some module or component you've already written. Designing stuff from the ground up is kinda tough for someone who's used to putting down some struct definitions and prototypes first.