My one complaint about WINDOWS*s is the admonition in the documentation NOT to overlap windows.
You can actually do this with another add-on library to ncurses. I believe it is called "panel", as in /usr/include/panel.h and /usr/lib/libpanel.a (-lpanel). I've never tried it, but it looks quite useful.

I have a few comments about your code:
  • I don't know what you think about single-line comments, but the fact is that they aren't part of C89. You might want to consider not using them.
  • Your indentation on the whole is pretty good, but there are some hiccups (wfillrect() for example).
  • Whenever you see code like this
    Code:
      do {ch = getch();}
    while ((ch != 'q') && (ch != 'Q')
    && (ch != 'n') && (ch != 'N')
    && (ch != 'y') && (ch != 'Y'));
  if ((ch == 'y') || (ch == 'Y')) return 1;
    you should immediately think "ctype.h". It makes things a lot easier.
  • Code:
      switch (r) {
    case 0 : return x; break;
    case 1 : return y; break;
    case 2 : return 3 - x; break;
    case 3 : return 3 - y; break;
  }
    Those break statements are unnecessary, of course. And you might be able to implement a fancier version like this . . .
    Code:
    n = (r % 2 ? y : x);
if(r / 2) n = 3 - n;
    Just a thought.
  • Please, please never have a variable called 'l' (lowercase L). It's annoying, and stupid, and hard to read, in my opinion.

Also, maybe it's just my ncurses implementation, but I do not see any text at all. (Again, this is a 64-bit Debian GNU/Linux lenny system.)

Something I implemented in my tetris a while back that I always miss in other tetrises is a "shadow" underneath the main block area that shows where the block will land. It helps avoid alignment errors, if you know what I mean. And you could also blink lines before making them disappear if you felt adventurous.

I'd post my tetris3 game, but I think it would be too embarrassing.