Here are instructions from another group:
Buy a 2' x 4' sheet of pegboard at Lowes or Home Depot. The standard size of the holes is 1/4".
Buy about 8-10 1/4" wooden dowel rods. They are 48" long. The number of dowel rods you buy is determined by how many pegs you want. Cut the rods into 4" lengths for the short spools and 6" lengths for the big spools.
Now comes the fun part. Lay the pegboard down on the floor or a table with newspaper under it to catch the glue drips!
Start at the top corner (either one) on the SECOND HOLE IN. Put a dab of white glue on the end of the cut dowel rod and insert into the hole at a slight upward angle.
Skip TWO holes and insert your next dowel piece. Continue on this way across the top. With this configuration you will have 16 pegs for spools per row.
For the second row start on the THIRD row down and repeat what you did for the top row.
By the time you've finished you will have 144 pegs for 144 spools of thread.
If you are using both the large and the small spools then when you get about 1/2 way down the pegboard leave THREE holes between each peg and THREE holes between rows and use the 6" long rods. The layout is pretty much up to you.
To attach to the wall: screw a 1"x2"x4' into the studs and then screw the pegboard to that rather than the wall itself. This way the top of the pegboard is set away from the wall and no little dowel stumpies will punch small holes in the wall. You don't need one at the bottom. You can paint it before hanging or leave natural.