The problem has to do with data consumption reports for users who are taking advantage of the newly added 3G mobile hotspot capabilities. The new iOS 4.2.6 update ensures that the data will be reported correctly, which is especially important given the data cap Verizon has in place.
Just as every other iOS update, all you have to do is plug your device into iTunes and hit update. It will take some time, but that is to be expected. Tell us what you think in the comments below.
source: Mobile Burn