The Blackberry Storm will let you pick what you consider the first day of the week when it is shown weeks in the calendar app. If you don't like the default (Sunday), you can change it by opening the calendar app and then pressing the Menu button. From the menu that is shown, click "Options" and then go to "General Options". You'll see a setting called "First Day of Week". Change it to what you want. Then hit the Menu button and click "Save" to make sure your changes are saved.