This has been discussed before as well. Here is the link to that thread:
https://bitcointalk.org/index.php?topic=2144807.0You might want to see the last post of that thread, by Vod. That is:
Guys - relax.
There will be no mobile app until we move to the new forum. Why make an app for this old outdated software?
So, there is no official App for Bitcointalk right now. There might be one after moving to the new forum as said by Vod.
I would suggest you (and all others reading this post) not to enter your credentials in any application as they can possibly be stolen.