Alex,
An iTunes sync will backup the data, but the downside is that if you want to restore, you have to restore all apps in the backup... you can't restore just a single app.
You can backup in the app. At the main Decks screen, tap "Edit", then "Export". If you don't have any pictures/sounds to export, you can send your export data by email. You'll get a .txt file that you can paste into my website if you need to restore. Change "Export To" to "Email", turn on Statistics and/or Export All Decks if you want, then Export.
If you have pictures/sounds you want to backup, change Export To to "Server". (You'll first need to assign the deck a "deck code" in the previous screen so you can find your deck on my website. After exporting go to my website to get your data:
http://orangeorapple.com/Flashcards/Export.aspxErnie