updated 01:50 pm EDT, Wed May 4, 2011
More changes to come
(Updated with info on Verizon tech) Apple has released a relatively minor update of iOS, 4.3.3. The upgrade does however fulfill an earlier promise by improving the security of location data. The size of the location cache file has been reduced, and the cache should no longer be included in iTunes backups. When Location Services are switched off, the cache is deleted entirely, Apple says.
The update is available through iTunes; download size is dependent on the device. Compatible hardware includes iPads, the iPhone 3GS, the GSM iPhone 4 and third- and fourth-generation iPod touches. Apple is not done addressing complaints with the security of iOS, as the next step is a planned "major" iOS update which will do on-device encryption of the location cache. When that might arrive is uncertain.
Update: For Verizon iPhones Apple has pushed out v4.2.8. Changes are identical to those of v4.3.3.