The IEEE Communications Societyis usually a walled garden, with white paper access available only to society members.
Today, though, the group offers free access to more than 20 white papers about VoIP.
Go to this page and download to your heart's content. But don't put it off... this offer is going away real soon- as soon as tomorrow.
I'd like to know if you've found any of these white papers interesting. If you have, post a TalkBack.