Okay, this isn't an obscene profit break - indeed, I've done a favor for anyone looking for a language app for their iPhone.
At the moment the iTunes store jumbles their language apps in amongst other travel apps. Some are easy to find - the name of the language starts the title of the app... others aren't so easy. And there's probably at least a thousand of them - from English to some other language to foreign language to foreign language.
So for example if you already know Spanish, why not learn French with a Spanish - French app? There's all sorts of languages on offer, from Albanian to Zulu.
I've sorted them by language, and you can find the list (across 11 blog entries) starting here. http://wyominginmotion.com/?p=155