Sorry I didn't clarify that - it's my car's voice command system. I can use this system to give voice commands to dial phone numbers on the fly or those saved in my car's contact list, and these voice commands will be executed on my iPhone. (Alternately, I can scroll through my iPhone's contacts using steering wheel commands and the stereo's display and select a number to call that way.)
It sounds like the 3.1 firmware will augment Bluetooth functionality to include voice command via headsets and such - that will be a nice upgrade.