The fourth iteration of iPhone OS 4.0 Beta has been released by the developers from Apple and it does offer from interesting insights as to what's coming next to the iPod Touch, the iPhone and the iPad.
First and foremost, it looks as if AT&T customers will be offered a tethering option which can be enabled within seconds although they'll have to get it approved by AT&T first. Tethering has been offered as a paid-for option for users on this side of the Atlantic since last year.
Whether this will be a boon or a bad thing remains to be seen. Having WiFi and 3G active at the same time on the iPhone is likely to drain the battery faster which may end up causing frustration amongst users.
The other "improvements" include a different default home screen that comes with a folder called utilities, which like its Windows counterparts, stores all these apps that are never really used often.
Gizmodo (opens in new tab) also says that the apps are generally a hint faster than before which is a sign that Apple has been tweaking things slightly for existing iPhone users.
The iPhone 4.0 is expected to be released sometimes in the summer and since the iPhone is likely to come out at the beginning of the month of June (at the WWDC), expect at least one more beta before the final one.