Hi there everyone.
I've got some good news for you about TeamTalk app for iOS.
Finally after waiting, Bearware.dk has developed TeamTalk for iOS and it's under beta testing right now.
If you want to help testing this amazing app, You can visit this link from their mane website:
A little note: I'm not responsible for anything happening with the app or the company itself.
I've tested the app myself and It look very fantastic and very accessible, But it need some improvements. Good luck.