SwitcherPlus is a handy little jailbreak that makes multitasking easier on the iPhone. Not only can you multitask directly from your lock screen, but you can also quit backgrounded apps in bulk.
All you have to do to get this working is install SwitcherPlus from Cydia, restart Springboard (this should happen immediately after installation) and both features will be on by default. To activate multitasking from your lock screen, just double tap the home button. If you want to quit a bunch of apps, tap and hold one of them to entire "wiggle mode" like you normally would but tap the little arrow in the bottom-left corner instead. This will quit that app plus all the apps to its right. This way you can quickly clear out your multitasking queue and potentially earn yourself a little extra battery life.
Haven't jailbroken your iPhone, iPad or iPod touch just yet? Head on over to our always up-to-date jailbreaking guide for the complete instructions.
SwitcherPlus (Free) [BigBoss]