> As it turns out, it looks like the crystal was dodgy.  I applied an
>external oscillator and the PIC happily started running.  So I'll buy a
>new crystal in the morning and 'touch wood it might even work... :-) :-)

If your new crystal doesn't work, and your using a prototyping board, it may
be that you have a problem with groundplanes. Once I had a problem with a
16C54 that only worked when the protoboard it was on was lifted an inch off
my metal desktop.