Phil,
I have a Radio Shack cordless phone that has a jack for such a
headset.
the headset, of course, is sold separately. I bought one, and use it
for conference calls, and for other situations where I need to use the
computer while on the phone.
I have also seen that feature on a few desk phones, but I haven't
looked at any of those recently.
I don't know of any house phone that supports bluetooth, but again, I
haven't looked.