Pair to do what? The iphone does not support disk mode or file transfer by bluetooth. The only thing you can do is tether by bluetooth if your carrier supports such & such is provisioned on your account.
I have the same problem. My iphone 4 and macbook pair but they won't connect. My iphone 4 also won't pair with my headset, a sennheiser VMX100, a reputable headset. Support said it was a software issue, but that apple did not have an action plan.
I'm glad I'm not the only one who can't get the iphone4 to pair with MacBook Pro... thought there was something wrong with the computer...I did get it to pair one time, but then it wouldn't connect...feel better now that I'm not the only one.