Many many years ago, Bluetooh version 2.1 updated its security scheme to something referred to as "Secure Simple Pairing". Not only was the process made more secure but also a bit more user friendly. Recently, I have started seeing devices using the Numeric Comparison protocol for pairing (e.g. the Nokia N8 and also a recent Samsung phone) where it's no longer necessary to enter a PIN but just to verify that the same number is displayed on both devices. Very neat!