Apple has released updates for iOS to change the crowd-sourced location database actions on the iPhone, iPad and iPod touch. This update does the following:
The new versions of iOS are 4.3.3 for the iPhone 4 (GSM model), iPhone 3GS, iPad, iPad 2 and iPod touch (3rd and 4th generation). iOS version 4.2.8 is also available for the iPhone 4 (CDMA model). These updates are available via iTunes when syncing an iOS device.
More information is available here (iOS 4.3.3) and here (iOS 4.2.8). There are no security fixes in these updates.