A friend of mine has an HTC Aria on AT&T. On his application settings screen, he does not have the option to allow installation of apps from unknown sources. Is there any way to change this option to allow him to install downloaded apps (*.apk files) without rooting the phone?

On the bottom of the home screen there is an icon for EMail. I don't ever want to use the default Email app. I only use GMail and would rather use the Google GMail app. How do I change where the icon goes and how do I remove/disable the other app? at&t Captivate (Galaxy S) Android 2.1