The finished product is a custom laptop bag for an OLPC XO laptop computer, but these instructions could probably be modified for many portable electronic devices. The bag core is made of high density foam, reinforced with paperboard. The bag is trimmed in polyester belting, has an adjustable strap, and a parachute buckle closure.
Step 1: Gather Your Materials
1 yard of fabric ($6.99)
2 pieces of 14"x22" posterboard ($0.78)
1 plastic parachute buckle for 1" belting ($2.29)
1 plastic strap adjuster for 1" belting ($1.29)
3 yards of belting ($2.97)
27" of 1" high density foam ($8.24)
Needles for hand stitching
The fabric I selected was from the calico/quiltmaking department, but I imagine you could use anything reasonably stable (not lightweight or flowy). Belt color should coordinate with fabric. I used two colors of thread, one to loosely coordinate with the fabric and one to blend in with the belt color. Consider your level of sewing skill if you want to use a contrasting color.