If you’re running a jailbroken iPhone, I guess that one of the tweaks you installed from Cydia is ProSwitcher. This simple yet powerful utility from Ryan Petrich allows you to switch between apps running in the background using a Palm Pre like “cards” UI, which is undoubtedly useful and easy to use. Just assign an Activator shortcut to it, launch it anywhere on your iPhone and switch between the apps you’ve backgrounded in a matter of seconds.
Now, you can install and use ProSwitcher on the iPad.