% convert the W9 to ps using pstopdf (part of Ghostscript)
% edit the resulting file and put this right before the 'showpage' operator
/Courier 12 selectfont
/inch {72 mul} def
/line {12 mul} def
1.5 inch 9.8 inch moveto
gsave (Firstname Lastname) show grestore
0 line -4 line rmoveto
% check the 'sole proprietor' and 'exempt' boxes
gsave (         X                                             X) show grestore
0 line -2 line rmoveto
gsave (1234 Main Street) show grestore
0 line -2 line rmoveto
gsave (Anytown, US 00123) show grestore
0 line -6 line rmoveto
% enter your social security number
gsave (                                                 1 2 3 4 5 6 7 8 9)
 show grestore
0 line -16 line rmoveto
gsave
% here's the handwritten signature in Bezier curves
1 inch 0 line rmoveto
currentpoint translate
-50 -1 -10 10 10 10 curveto 
currentpoint translate
20 0 20 -14 0 -15 curveto
currentpoint translate
-15 0 -15 7 0 10 curveto
currentpoint translate
20 3 40 0 40 0 curveto
currentpoint translate
10 0 10 -5 0 -6 curveto
currentpoint translate
-60 -10 -58 1 -35 2 curveto
currentpoint translate
30 3 100 0 100 0 curveto
stroke grestore
% and the date...
gsave (                                               2007-10-30) show grestore