I use Bubble Letters to teach students their letters by letting them color inside of each letter, fill the letters with stickers, fill the letters in with thumbprints or dot paint, or fill in each letter with things that start with that sound. (Ex. Fill in the P with "pom poms")
Other ideas include:
1) Letting students cut out and glue pictures from magazines that start with that letter AROUND the letter.
2) Laminating the letters and using them with expo markers or as play dough mats.
The possibilities are endless!