No rooting needed. In Android Market there are several launchers to choose from. Many people say good things about GOlauncher, but I really like this Launcher Pro.
Just download and install the Launcher. After installation, when you press home, Dell will ask you to select the launcher. Tick the default and choose the desired launcher and there you go..
Launcher Pro lets you customize the home screen appearance, behaviour, icon size, rows and many other things