Also an idea from Dr. Jean's blog:
Photocopy your iPad open to a horizontal text-input screen on cardstock, mount and laminate. Or attach inside a file folder. Kids can "type" their names, the alphabet, sight words, etc. How fun is that! This also develops early keyboarding skills as it familiarizes kids with a QWERTY keyboard. In this world of high-speed electronic communication, keyboarding is a crucial skill!
You could also make a class set mounted on cardstock and/or tagboard, and use for whole class letter ID activities and sight word practice. Maybe even blow up a big one on the wall or Smart board! Oooh, you could make a Smart board game where touching the key brings you to a page with objects or a game for that letter!