1. Question: What do we call it, when the Pope stops being Pope? I used the word "retire", but that's obviously not accurate, because that makes it seem like he's retiring from a job. After all, the priesthood isn't a job. He's always going to be a priest, no matter what. He's just not going to be performing active ministry as Bishop of Rome anymore.
The official word that Pope Benedict used was renuntiatio. It's where the English word "renounce" comes from, although it usually gets translated as "resignation". So I'm going to go with that, and say the Pope resigned. It's not a perfect description, because he didn't submit a resignation to anyone, but there you have it.
2. Some people are making a fuss about the possibility of an African Cardinal being elected Pope. People say he will be the first black pope.
Wrong. There have been three Popes from Africa. Most popes have been Italian, though.
3. Some people have also asked if Pope Benedict will be able to use papal infallibility, post-retirement. No, he will not. As Lumen Gentium states, the Pope enjoys infallibility in virtue of his office. Logic dictates that when he ceases to have the office, he ceases to have infallibility.
Fun fact: Pope Benedict XVI has been Pope for eight years. In that time, he has made a grand total of zero infallible statements. Infallibility is not something that gets used lightly, you know.