Can you please clarify what you are trying to do here. There are no taxes due for simply converting one currency to another. If you bought foreign currency futures at one rate and then later sold the currency at a gain, then there would be tax implications.
Are you inquiring about the rules for bringing foreign money into this country?
Who will be receiving these funds (individual or corporation)? Who is sending the funds and what is the purpose for them sending the money?
The fact of transferring the money is not a taxable event.
In case you transfer the money to US - if the amount is more than $100,000, you are required to file form 3120 - http://www.irs.gov/pub/irs-pdf/f3520.pdf (see instructions for details - http://www.irs.gov/pub/irs-pdf/i3520.pdf) to declare transfer from the foreign country. There is no tax associated with this form.
To identify if any of the money are taxable - we need to clarify the reason why the money were paid. If the money are from inheritance, gift, etc - it is not taxable income; If the money are payment for services - the net taxable income is calculated as gross proceeds minus business expenses. If the money are payment for sold assets - the net taxable income is calculated as sale price minus the basis of assets.
Please let me know if any clarification is needed.