While Apple’s iPhone SDK will give far more official flexibility for third-party developers, there are still limitations on what functionality coders will be able to take advantage of.  Not permitting background processes is one of the better known restrictions, but Apple has also said that third-party software will not be able to access the dock connector or Bluetooth either.  It’s forced companies to come up with clever solutions for getting their peripherals to talk with the iPhone; Gadgetell spoke with PosiMotion, whose G-FI GPS for iPhone product will use WiFi to funnel positioning data into the cellphone.

Gadgetell:  To me, it would seem very risky to build something Apple may not allow, how do you minimize this risk?

PosiMotion: We are in the process of gaining Apple product certification 

Set to release this Summer, the G-FI receiver will apparently be compatible with both the iPhone and iPod Touch, and come with software based on the official SDK for both devices.  G-FI will also be compatible with other WiFi enabled devices, such as laptops.

Using WiFi rather than the more traditional Bluetooth to circumnavigate Apple’s restrictions is also the tactic of PacketVideo, whose TV tuner will use the wireless networking standard to send mobile TV to the iPhone.