iPhone developers have been downloading the iPhone 3.0 OS SDK since it became available earlier this week. As they sink their teeth into the new SDK, lots of gems are popping up that suggest new, unannounced features -- and devices! -- are on the way.One of the first neat new features to be uncovered is the possibility of tethering the iPhone to a laptop. This would let the user connect their laptop to the Internet via the iPhone, rather than a separate wireless modem. According to iLounge, one developer has cracked this new feature and discovered that it can be tethered via USB cable or Bluetooth. The hacker claims he doesn't know how he enabled the feature. It happened by accident when he was "hacking around."

Tethering has long been a sought-after feature for the iPhone. Apple addressed the issue during its keynote on the 17th, saying that the feature is definitely possible. Apple also said that it is up to the network operators to make tethering a reality.

Next up is a nifty use of the iPhone's GPS and Apple's MobileMe service. AppleInsider reports it has found a new service called "Find My iPhone." The service will allow iPhone owners who also are MobileMe subscribers to find their lost or stolen iPhone via its GPS data. This would be a great help to anyone who has misplaced their iPhone, or had it stolen. It also would be great for security, as recovering a lost mobile device can mean protecting user privacy and possibly corporate information as well.

Last up, some bits of code in the SDK suggest OS 3.0 will work on future, unannounced devices. Apple uses some code names for the different hardware builds of the iPhone. According to Ars Technica, the current nomenclature for the 3G iPhone is iPhone 1.2. Code seen in the 3.0 OS show iPhone 2.1, and even iPhone 3.1. These code names don't correspond to any known iPhone models, and thereby could represent new models that are planned for future release.