My Spellings is an app that lets you practice your spelling using tests. It lets you use your voice to record the words, and then you have to type the word correctly. You can set up multiple 'tests,' and record lists of words for practice and testing, which seems like it would be incredibly useful to parents of school-aged children, or even for your own practice.
The developer was kind enough to share his thoughts on adding OpenDyslexic:
My Spellings aims to help with the age old spelling test. Create your own spelling tests using the microphone on your iPad, iPad mini, iPhone or iPod touch. Then use the 'Look, Say, Cover, Write, Check' method to practise and learn the spellings. When you are ready, take a test and then email or message the results to your friends, parents or teachers!
Our aim is to make My Spellings accessible to all, therefore including the OpenDyslexic font was a natural next step. With the most recent app update, we added the option to display key text either with our normal font or with the exciting OpenDyslexic font. My Spellings is designed to have a positive impact on language learning, and with the inclusion of OpenDyslexic this impact will only deepen.
Get it: http://appstore.com/myspellings
Developer website: http://myspellingsapp.com