Instant Mirror is a helpful tweak to some who cannot find a mirror in many places. If you find yourself putting on makeup and not having a mirror, this tweak can easily substitute carrying a mirror around. Best thing about Instant Mirror is that you can always hide it and look at your lockscreen. One tap of the home button does that, two taps still brings up iPod controls. It seems to be a pretty solid built tweak and I don't even notice a difference while turning on my lockscreen. Check out Instant Mirror in Cydia for $1.49.