This is a simple tweak which allows you to scrub music right from the lockscreen without opening the music.app. The scrubbing only works for the default music.app.
This tweak is tested on iOS 5 and above. Currently it works only on iphone 3gs and above, iPod Touch 3G and above. Future updates will bring in iPad support.
You can purchase LSScrubbing from the Cydia Store for $1.99.