For their birthdays, I made the boys super simple pillowcases. Apparently they were a hit so here's a tutorial (and I'm going to enter the tutorial in this little contest; check it out):
Buy 1.25 yards of 45 " wide flannel or soft cotton (you can get by with a yard but it's tight).
Trim off the selvedges if you're feeling picky. Fold the fabric in half with back sides together matching the selvedge edges (actually, your fabric should be a square if you bought 1.25 yards so it doesn't really matter which way you fold it. If you only got 1 yard of fabric, definitely match selvedge edges).
{If you do much sewing, you're probably used to sewing with good sides together but this is the trick of french seams, back sides together.} See?:
Sew along one short side and all the way down the long side with a scant 1/4 inch seam. Here's a poor diagram (sorry, no scanner so a photo of a sketch will have to do):
Now, turn your pillow case inside out. On the open end of your tube, fold in the raw fabric edge about 1/4-1/2 inch and stitch down all the way around. (this will make it easier to hem later). You can see on the image below that the narrow hem is stitched.
Now comes the fancy bit! You're going to sew over your first line of stitching, encasing the raw edges from the previous seam allowance in the new seam allowance. At this point, it may help to press your pillowcase making sure the edge seams are ironed out. Then, stitch using a seam allowance just wider than 1/4 inch (to make sure you entirely encase the original seam). Make sense? Here's a photo:
As you can see, you're sewing with the good sides together. And,you can tell that the edge of the presser foot is going along the previous seam (on the right in this view).
One other tip, at the corner of the pillow case, plant the needle in the project when you're 1/4 inch from the edge, lift the presser foot and pivot the fabric. This gives a perfect 90 degree corner. Sorry for the fuzzy photo but maybe you can see here? (probably not, but you can see how the edge should look):
The final step is to fold in the open end and stitch a wide hem in place. I used my pillow off my bed to estimate how much I needed to fold it to make the right length pillow case. (I think it was about 5 inches for a standard size pillow). Just fold it to the inside and stitch more or less over your previous hem stitching (again, ironing first may help keep it even). I didn't photograph this step but it's simple.
That's it. Enjoy! (and if you really love pillow cases, let me know and I can write up directions for my mother-in-law's fancy pillow cases.)