LG HBS-700 Bluetooth Headset not pairing with my iphone 4s, and the phone is in discoverable mode and searching

I had the same issue, fixed by using the Manual mode for pairing. From the manual:

2) Manual Pairing (Pairing with another phone or re-pairing)
a) With the Power off, press the CALL button and move the power switch to the
'ON' position at the same time for 4 seconds.
b) When the headset enters Pairing Mode, the LED indicator will show a solid
blue light. After the procedure repeat Easy Pairing steps c through f.

Steps C through F are to go to the bluetooth settings area and manually select the HBS-700 for pairing.

Turn the bluetooth radio off on your old phone. Turn on the hbs700. Your earpiece should automatically go into pairing mode when it does not detect your old phone. Turn on the bluetooth radio on your new phone and search for your hbs700. Connect to and you're done.

The LG HBS 700 will automatically go into pairing mode if it does not detect the last device it was paired with. So, make sure all other bluetooth devices are off, turn the earpiece on and wait for the status light to show solid blue. Then you can turn on the bluetooth on your other device and search for the HBS 700.

Pairing with iPhone

1. Connect the iPhone Dual Dock or iPhone Bluetooth Travel Cable to a USB 2.0 port on your computer (not on the keyboard).
2. Connect iPhone and the headset to the dock or cable. The headset pairs with iPhone automatically.

Pairing iPhone Bluetooth Headset with another Bluetooth-enabled deviceTo pair the iPhone Bluetooth Headset with another wireless device, such as a Bluetooth-enabled phone or computer.
Step 1: Set the headset to be discoverable

1. Turn off the headset.
2. Press and hold the headset button for about eight seconds, until you hear the startup tone and then five quick high beeps.
   
   The headset is now discoverable and will remain so for about five minutes. The status light blinks while the headset is discoverable.

Step 2: Turn on Bluetooth on the other device and search for devices

1. On the device, turn Bluetooth on and set the device to search for other Bluetooth devices.
2. On the device, choose iPhone Bluetooth Headset and enter the PIN code 0000.

See the instructions that came with your other Bluetooth-enabled device for more information about pairing it with Bluetooth devices.

It should automatically go into pairing mode if it does not detect the last device you paired it to when you turn it on. After startup it should say "ready to pair". Make sure all other bluetooth devices are turned off before turning on the HBS730

Turn off the headset. Keep the Call button pressed, turn the headset on and wait for the 3 bips (~4 seconds after turning it on). Then release the Call button. The solid blue light will indicate the pairing/discovey mode.

Once you make your iphone discoverable, then put the Plantronics 903 headset into pairing mode by pressing the power button until it flashes red and blue. If it's not flashing red and blue, it's not in the pairing mode. Below is a link for the user guide which has the pairing instructions:

Plantronics BackBeat 903 Pairing Instructions

Good luck from Headsets Direct!

the bluetooth of iphone is not compatible with this.get the bluetooth application installed from itunes store to maki it compatible.

To pair the headset with your phone:
Turn on the headset. Then turn on bluetooth in your phone and search for bluetooth device.
When your headset is detected, just select it and follow onscreen instructions to pair it with your phone.

iphone works well with LG HBS 200, I am listening to music in iphone though LG HBS 200 right now..it works like charm