This tweak can customize the color of the clock and date label on your iOS lockscreen. Unlike the LockDate Cydia tweak (which Stud happened to post) where you can only customize the date label on your lockscreen, with ColorClock you can customize both the clock and date label. The only limitation imposed on the ColorClock Cydia tweak however, is that you can only customize the color of these labels via RGB sliders.

This is a good site to get a RGB values:

It's free on the ModMyi repo.