QUOTE
create a new document 1x2 with transperant BG
get your pencil tool and set it to 1px
click on the top half of your doc
edit>define new pattern. name it something like horizontal scanlines
for diagonal scan lines:
QUOTE
create a new document 3x3 transperant BG
get pencil tool at 1px
click the top right corner, middle, and bottom left, depending on which was you want the scanlines to go.
edit>define new pattern. name it something like diagonal scanlines
for vertical scan lines:
QUOTE
create a new document 2x1 with transperant BG
get your pencil tool and set it to 1px
click on the left half of your doc
edit>define new pattern. name it something like horizontal scanlines
there you go, now you have a few scanline patterns. another pattern that i like to use is horizontal and verticle scanlines together to make a grid.