[Getting credentials from an app]

Yes last time I looked those apps Cert Pin. Also you will find a lot of apps with use OAuth so don't store or transmit user/pass pairs. Though you can still use the OAuth token. Though the token is often limited in the functions it can do.

So does this mean that we can just gey their OAuths and not their exact credentials? Is this because it's pre logged in?

[Getting credentials from an app]

I'm wondering how do apps(i.e Facebook, or Twitter) on an iphone or android device transmit the username and password?

We can always do a MITM attack using an SSL Strip to get the login credentials from a PC. However, how does the new Wifi Pineapple Nano get the login credentials if I am using an Facebook app(over wireless)? Can we still use the SSL Strip or is there any other MITM attack?