DLTK-teach.com is a great resource for learning activities. I recently ran across their tracer pages and had a great idea. I have been printing them off and laminating them. I print them double sided--so A and B are on the same paper, C and D, and so forth. Then I laminate. Then my girls can use either a dry erase or a wet erase marker and practice letters. You can also use a permanent marker and erase with finger nail polish remover, but I am not the type to hand my kids permanent markers.
This is a great thing to have on hand for learning time. It is also great when you are cooking something in the kitchen and your child needs something to do.