Ipanema Beach is located in Rio's Zona Sul (south zone) which is easily accessible by bus or metro.
The Metrô Rio subway system is very useful for travel from Ipanema through Copacabana to Downtown and beyond, although it closes after midnight (24 hours during Carnival). The air-conditioned subway is safe, clean, comfortable, and quick, and has much better signage, etc., than most transport in Rio, making the lives of foreign tourists easier. There are two main lines: Line 1 (Orange) has service to Ipanema (General Osorio), the Saara district, and much of Downtown, as well as Tijuca. Line 2 (Green) stops at the zoo, Maracanã stadium, and Rio State University. The two lines are integrated between Central and Botafogo, so check the train's destination if you board within the integrated section for a destination in the Zona Norte. A one-way subway-only "unitario" ticket is R$2.80 (Jan 2011). The ticket window will give you a card that you insert in the turnstile; don't pull it out unless you've purchased a multi-trip or transfer pass. Rechargeable IC cards (minimum charge R$5, no deposit required) are also available and definitely worth getting if you'll be in town for a few days.
Since 2003, the Metrô company operates bus lines from some stations to nearby neighborhoods which are not served by the subway system. This is particularly helpful for places uphill such as Gávea, Laranjeiras, Grajaú and Usina. Since the city grew around the Tijuca Range mountains, these neighborhoods will never be served by the subway, but you now can take the integração (connection) minibuses. The company calls it Metrônibus and Metrô na Superfície (literally, Subway on Ground), but actually they are ordinary buses in special routes for subway commuters. You can buy tickets for these - just ask for expresso (pronounced "eysh-PREH-sso", not "express-o") when buying a ticket, then keep it after crossing the roulette (prices range from R$ 2.80 to 4.40, depending on the transfer you want, as of Sep 2010). When you leave the subway, give the ticket to the bus driver (who shall be waiting in the bus stop just outside of the station). If you buy an ordinary ticket, you won't be able to get this bus for free - then it will cost a regular fee.