Well, it may not be the best way, but it works for me- I pair my phone with my zumo, then pair that to my scala rider headphones. That way I'm able to listen to music from the phone, accept calls, and hear the annoying garmin lady tell me which lane to get into. When a call comes in, the number (or id I've assigned) comes up on the zumo's screen with little decline? or answer? buttons.
The phone resides in my pocket, or sometimes in my tank bag. I've got mine set up to link to each other automatically when both the phone and the garmin are on.
Expensive combo, but altho I've never used the feature, the garmin has the phone numbers for many poi's built in and the capability for me to call ahead with the push of a button to find out if a place is open, or make hotel reservations or find out hours or whatever.
Hope that answers...
Chris in boston