Saving passwords and/or usernames?

how do i make it so my login app saves passwords or usernames that is entered into it

Model: Macbook Pro
AppleScript: Version 2.3 (118)
Browser: Firefox 9.0.1
Operating System: Mac OS X (10.6)

You need to save them in your app’s preferences file. Search here for messages containing NSUserDefaults and you’ll see plenty of info about how to do it.