BlackBerry, Android, and iPhones are the three big names in smart phones today.
Android has its "hardware buttons". Menus and navigation are often at top of the screen. Buttons orientate on the default android buttons and UI.
iOS splits the menus and navigation in two parts. At top is the Navigation like back button, title, ok and cancel. At bottom there is navigation like the tab bar to switch between views.
Blackberry has its own design guidelines.