Modal window Cocoa app
I just recently started making apps for OSX desktops and I want to have the users click a button and a window come up, similar to the following screenshots. What is that window that comes up called? You can't quit the application when you're entering the information. I tried looking for ways to make an NSAlert do this, but I was way off. Can someone please point me in the right direction? Thanks in advance!
The common name for what's shown in those images is a "sheet".
Technically, this is generally accomplished using 2 NSWindows (or NSPanels), one of which is termed the sheet, and which is shown modally against the second window, which serves as the main window the sheet appears from.
While I believe you can use NSAlert's for displaying simple dialogs in this fashion, the setup shown in those images was most likely accomplished by using a custom sheet. See Using Custom Sheets.