Engraved text is easy: draw the text white, then move upwards one pixel and draw it black.
Two ways to do it:
1. Duplicate every text field in your nib, with a black version overlapping a white version. Hard to edit the text, though, since you have to do it twice, and once on a field that'll be hard to click.
2. Make a trivial subclass of NSTextFieldCell, and override -drawInteriorWithFrame:inView: to twiddle the rect and the colors in between calling super twice.