I am sure you have been already using iPhone App switcher from Homescreen or Springboard which is normally used to switch between one app to another. Now a jailbreak tweak called LockScreen Multitasking has been released which allows you to launch your iPhone App Switcher directly from Lockscreen means you won’t require to unlock your iPhone. Moreover, if you are using a passcode option even then this jailbreak tweak allows you to launch App switcher but you won’t be able to open apps.
In order to get this Cydia App on your iPhone, iPad and iPod Touch, make sure you device is Jailbroken. Click here to tethered Jailbreak iOS 5.0/5.0.1 On iPhone 4, 3GS, iPad, iPod touch using RedSnOw or here for Snowbreeze.
LockScreen Multitasking is a free Jailbreak tweak available for only iOS 5 and can be downloaded from ModMyi repo. Once installed, It will neither require any configuration nor will create any icon on your springboard.