HeadphoneLauncher is a new tweak that allows you to view and launch apps from the Lock Screen. The tweak launches the selected apps every time your headphones are plugged into your iPhone. You can choose and rearrange the order that the apps appear by using the Headphone Launcher panel under Settings.
HeadphoneLauncher will also display the media controls on your Lock Screen. This is a great tweak for people who like to listen to music while walking. Unfortunately, it doesn't seem to work with Siri Board which would've been a nice bonus.
HeadphoneLauncher is $0.99 in the Cydia App Store under the BigBoss repo. Your device must be jalbroken to download.