Quickly access any app on an iPhone iOS5 using home or volume buttons? Is there a way to quickly access apps by holding down the home button, volume button or double tapping any of the buttons while in lock screen. 

I believe there was a way to do it with a Jailbroken iPhone but I am looking to do it with iOS 5. 

Any suggestions? 
Or will I just have to wait for an iOS 5 jailbreak?
Double tap the home button → It works great.