In most Brazilian cities the current is either 110V or 220V, 60 cycles (Porto Alegre have a wide 110V network, ans a small 220V one). Most major hotels have 110V and 220V sockets, but to avoid ruining your appliances, it is advisable to consult the hotel before plugging anything into an outlet.
The wall sockets in Brazil normally have two round pins (type C). Some outlets may require a ground pin. Conversion plugs, suitable for dual-voltage appliances can be purchased at many airports and electrical stores in Brazil.
In the picture, the most common plug. The wall part may also accept type A (flat) plugs.