Impact on Mobile Warriors: None unless you're an iPhone users. And if youare n iphone usser with ATT, then there is no impact on you except the upgrades you'll get. Increase stability, better browsing experience, and the ability to download podcasts over Wi-Fi or the provider's wireless network.
Now, for mobile folks not aware of the cat-and-mouse game played between iPhone hackers and Apple, every update provides an opportunity for iPhone users on the iPhone Dev Team to undo the locking work done by Apple's iPhone software team.
Essentially, every update means hackers on the iDT would break Apple's locking scheme (not really locking depending on how you think about it. Okay, it sort of it) but also Apple would undo whatever the iDT did previously.
In a way, you have to short of think of Apple as the underdog here. Just a bit of history. When the original iPhone came out 18 months or so ago, it was only available in the United States during the initial year. However, more were sold than was actually being used on the ATT network because people were able to unlock them for use on other networks like T-Mobile in the US and whatever GSM networks else where around the world.
There was rumors that a million unlocked iPhones were sold in China alone. I knew someone who is a broker there who has one. Others gave them out to clients as sort of a status symbol.
Now, with the iPhone 3G, there really is no way to unlock the newer iPhones via software, although they might be close (the original iPhone can be easily unlocked). And the need for jail-breaking has greatly diminished with the introduction of the app store and apps in general. However, the jail-break community is still going strong and offers many apps that Apple will not allow on iTunes (tethering apps quicking comes to mind).
Anyway, just in case you're wondering all the craze on the blogs today, this is why.
Note: iPod Touches can also be jail-broken as well. No need for unlocking there.