Here are some links for making your own fabric labels for clothing, bags, plush toys, etc.
Iron-On Transfer Labels
Printed Labels - Labels printed on special ink jet fabric
Washable Printed Labels
Embroidered Labels - Using machine embroidery *required computerized sewing machine*
If you've had custom rubber stamps made you can use fabric inks to stamp labels.
Here are a few links to Etsy sellers who offer custom fabric labels.
WorldwideLabel - Woven labels
Custom Couture Label Company Multiple styles of fabric labels
Herjodren - Washable printed labels and other print products