The currency of Thailand is Baht (THB). 1 Baht is divided into 100 satangs.
There are 20, 50, 100, 500 and 1000 Thai Baht notes. 1, 2, 5 and 10 Thai Baht coins are also available. Seen less frequently are 25 and 50 satang coins.
1 Thai Baht = 1.3 Indian Rupee Approx.
Its possible to exchange foreign currency at most tourist locations and banks in Bangkok. Some banks might also be willing to exchange Indian Rupees. However, the THB-INR rate offered is often very poor. If you are flying in from India, it is advisable to carry hard currency (USD, Euro etc) notes or traveller's cheques. Carrying forex cards issued by many banks in India are also a good alternative.
Using your International debit or credit card card to withdraw money at ATMs should also not be problem. Make sure to ask your bank in India about withdrawal fees. Some Indian banks are known to charge exhorbitant withdrawal fees on overseas ATM withdrawals.
If you are carrying Indian Rupee, it might be possible to get good rates at exchanges not operated by banks. One such reliable exchange which would accept virtually any currency in the world is Vasu. It is located in the Nana area (near BTS Nana next to the Subway restaurant).