I love making a pillowcase to match the quilt. I do it with the "hotdog" method. Three seams, and you're done! Here is a link to a free pattern for these:
http://extension.usu.edu/files/publi...2006-102pr.pdf
I am a volunteer 4-H leader, and teach this method to our 4-H students. It's so quick and so fun. You can also finish the inside seams with a french seam to enclose the raw edges. And recently our quilt guild made 36 of these pillowcases at a guild meeting (about two hours, 10 machines, 24 quilters) to donate to our local children's justice center.