To learn a bit about using XCode, program in Objective-C using Cocoa and play with bluetooth and my phone, I wrote a simple bluetooth serial terminal. It simply connects to my phone (or any bluetooth device), opens a communication channel, and lets you send characters through it as if it is a serial connection. With my phone, this allows me to do pretty much everything that - list, read, send SMSs, contacts, check battery status, signal strength, etc.
Nifty! Here is a picture:
Download it, give it a whirl. I will one day update it to use Core Data so it handles SMSs and contacts in a nicer way then dumping out as text.