Foreign visitors seem to be concentrating so far on chain and well-known hotels listed on the internet for the games, which is only a part of the room stock in Rio. There are also pousadas (B&B type lodging-- like in Santa Teresa for one example www.camaecafe.com.br) and comfortable hostels with private rooms that many World Cup visitors ended up using. Some people were renting rooms in their homes for the World Cup, in all sorts of neighborhoods from chic to quite poor. Many visitors rent apartments for their stays, at all times of the year.

(Get a city map and follow along.)
Most foreign visitors stay in the Zona Sul (south zone) neighborhoods of Copacabana, Arpoador, Ipanema and Leblon. Other good central neighborhoods that are usually more reasonably priced are Laranjeiras, Botafogo, Gloria, and Flamengo. There are many business hotels in Catete. Many events seem to be planned for Barra de Tijuca, which is located fairly far on the south side of the city. Traffic has usually been a major headache for anyone staying there and wanting to see the city sights, but new transportation options have been promised for the games.

The informational site www.ipanema.com is a good introduction to the city, the neighborhoods and attractions, and lists some hotels.