What you need to know before visiting Indonesia
Upon visiting Indonesia, you will most probably enter the country from Jakarta or Denpasar, Bali. It is quite easy and straight forward to enter Indonesia. Chances are you will not need any visa to enter, and if you actually do, you can always get a visa on arrival which costs roughly about 25 USD. There are some countries, however, that may require an entry visa upon arrival.
Indonesia's main airport, Soekarno Hatta International Airport, is located just on the outskirts of Jakarta and (depending on the traffic) about 1 hour away from the CBD. You can navigate your way into town by bus or taxi (or if possible, get your hotel to pick you up). Taxis are quite reliable and make sure you get the ones from Blue Bird, Silver Bird or Express, as they are the most recognised and widely used ones. A trip to Jakarta's CBD costs anything between 15 to 30 USD.
Other than that, Indonesia's other point of entries for International tourists are Denpasar (Bali), Medan, Palembang, Lombok, Bandung, and Surabaya.
Indonesia's main currency is the Indonesian Rupiah (not to be confused with the Indian Rupee), denoted as "Rp". 1 USD on average equals Rp 10000. The smallest nominal values for coins are Rp 100 and the largest Rp 1000. The notes values are: Rp 1000, Rp 2000, Rp 5000, Rp 10000, Rp 20000, Rp 50000 and Rp 100000.
Credit cards are widely accepted in major areas such as Jakarta and Bali, especially VISA and Mastercard. American Express is generally accepted, but not as much as the afore mentioned card associations.
To withdraw cash, international cards can normally be used in ATM's. Use ATM's from major banks such as Bank Mandiri or BCA, as they are located almost everywhere.
Language and Communication
Indonesia has more than 300 spoken languages and dialects, but are unified through its national language, Bahasa Indonesia. The language itself is rooted from Malay language with heavy influence from Arabic, Dutch and Portuguese.
English are commonly spoken in major areas such as Jakarta and Bali, so there should be minimal issues there. The older generations (born before the 1940's) are normally very fluent in Dutch.