"In the Light of the Law", the fine blog of canon lawyer and professor Dr. Ed Peters (he teaches at Sacred Heart Seminary in Detroit), is an essential and trustworthy source at any time, but perhaps especially during this unusual time, on the cusp of Pope Benedict XVI's final day as pontiff and on the verge of the conclave. As Dr. Peters notes, there is a real sense in which the Church is, well, winging it:
Aside from the resignation itself—the canonical legality of which is incontestable—Pope Benedict’s startling decision to leave office has occasioned much confusion in Rome and around the Catholic world. The simple fact is that the Catholic Church, at every level, has virtually no experience in dealing with ex-popes.
Beyond the barest of canonical points (c. 332 § 2), almost everything about Benedict’s future—his status under law (canonical and international), title(s), appropriate dress, relations with peers (assuming he has any), and so on and so on and so on—must be fashioned practically from scratch. One should not assume that any announcements being made about Benedict’s future are based on the authority of some arcane-but-accessible protocol tome for dealing with ex-popes, because there is no such tome. We’re making most of this up as we go.
History’s not much help either. Setting aside some first millennium episodes that are almost too bizarre for words, the last pope to resign (Gregory XII) had been elected and tried to govern under conditions that would shock the conscience today. The only other pope to resign (Celestine V) was promptly arrested and died in prison. None of this is remotely useful for predicting Benedict’s future.
Read his entire post, "Some distinctly non-canonical musings on the status of an ex-pope." And be sure to keep up with his blog, which has been invaluable for many years, and will undoubtedly be the same during the eventful weeks ahead.