Useful Funciton modules for Amount and Currency

CURRENCY_AMOUNT_SAP_TO_IDOC	Convert currency to IDOC format
CLOI_PUT_SIGN_IN_FRONT	Move the negative sign from the left hand side of a number, to the right hand side of the number. Note that The result will be left justified (like all character fields), not right justifed as numbers normally are.
CONVERT_TO_FOREIGN_CURRENCY	Convert local currency to foreign currency.
CONVERT_TO_LOCAL_CURRENCY	Convert from foreign currency to local currency
CONVERT_AMOUNT_TO_CURRENCY	Convert an amount from a currency to another (exchange rate taken from database tables)
CONVERT_CURRENCY_BY_RATE	Convert an amount from a currency to another, according to the passed exchange rate
BAPI_CURRENCY_CONV_TO_EXTERNAL	Conversion of Currency Amounts into External Data Format
BAPI_CURRENCY_CONV_TO_INTERNAL	Conversion of Currency Amounts into Internal Data Format
CALCULATE_TAX_FROM_NET_AMOUNT
SPELL_AMOUNT	to get Amount in words
HR_IN_CHG_INR_WRDS	Changes INR amount to words.