I'm about to dive into this question as well. I'm working on a Android interface to a project management website for work. I figured out how to push my username and pwd from my py scripts to log-in into the website, but now I need to figure out how to store it on my phone (in the app).

Give this a try:
Google + PreferencesFacade

further reading:
Google + android data-storage

(sorry, can't post links yet)

 

Just ran a quick test and its working:

# Storing
self.droid.prefPutValue('key','value','FileName')

# Retrieving a value
print self.droid.prefGetValue('key','FileName')

# Retrieving all
print self.droid.prefGetAll('FileName')

You may have to do some further work to encrypt your information (ie pwds), but its a start. I'm also not sure if these values are available to other apps or if this if private to the particular app. Also, I've read a bit on issues with rooted phones and storing data - bottom line is encryption.

 

I believe this answers part of my question:
prefPutValue - uses "MODE_PRIVATE" when writing to preferences. Save values to the default shared preferences is explicitly disallowed.