According to CultofMac, iPatch will release an iPhone 4 mod that causes the Apple logo on the back of the iPhone to light up when the screen lights up. Reportedly they will release details of the mod on their Twitter account @iPatch_iPods.

From CultofMac:
This awesome mod is expected to cost less than £100 (approx. $159) when iPatch begins offering the service, which they estimate will be in less than a month. What’s more, the process will take less than an hour and it uses your iPhone’s original rear casing without adding any increase to its depth whatsoever.