Quickly Switch Between Two Apps with LastApp

For all you speed demons out there, iOS4's multitasking is a little bit cumbersome.
Sure you can work in one app, load up the switcher, and then select the app you would like to switch to, but in most cases, there�s only a couple of apps you need to use simultaneously.

If you find yourself switching back and forth between two apps quickly, i.e., App Store and Safari, then LastApp is a true gem. This time-saver has been around for a while, but it hasn�t received much attention�
Think of it as CMD-Tab/Alt-Tab for the iPhone; with a quick Activator gesture, it will instantly launch the previous app you were using. This method is much, much faster than double-tapping the home button, selecting an app from the task switcher bar, and launching back into it.
Once you install it, go to the Activator settings pane in the Settings app, go to In Application, then choose your gesture (I liked �double tap status bar�). Now whenever you�re in an app and want to go back to the last one, double tap the status bar (or whatever you picked) and you will instantly switch back to the last app you were using.
This is a free app with no Springboard icon. It is available in Cydia from the BigBoss repo (for jailbroken devices only).