I am trying to pair my iphone 3g with a samsung impression. The samsung pairs with the iphone but the iphone can't find the impression.

Plantronics has really good instruction on their site. And if that does not work their customer service is excellent if you call them.

Hi dear the bluetooth provided by apple can only pair with apple phones .So will not be able to pair with other phone brands like nokia samsung etc. For any phone or apple apps,hacks and games send your querry to [email protected]

Motorola aren't made to pair with the iPhone, its most likely just down to software difference, so its not a problem with the Motorola device or the iPhone, they just aren't compatible, if you visit the Apple website it will have lists of bluetooth devices, not all Apple, that work with the iPhone.

On your phone. goto the Bluetooth menu and select "Add Device or Add Headset"

Refer here to put the headset into pairing mode:
http://www.fixya.com/support/r5009033-put_most_bluetooth_headsets_into_pairing

The iPhone unfortunately does not pair with just any device, it would be best to check compatibility before purchasing a new peripheral for your iPhone.

You will need to update your navman firmware
If it is a old model gps check the navman site for compatability.

pin code 0000

iPhone has had bluetooth since the first model in 2007. With iPhone OS/firmware 3.0 (free for all iPhone users), iPhones are fully A2DP compliant and link with Mazda bluetooth.
My current experience is with a 2010 Mazda3 and iPhone 3GS, where I get phone and iPod functionality via bluetooth (yes, without jailbreaking), though the steering-wheel controls are limited to play/pause and volume only.

Make sure the headset is off. iPhone--Settings--Bluetooth---On---Press and hold the answer/end button for approx 5 secs until lite turns sold blue. It works