If
your parents are not US citizens or residents of the US, there are no US tax
implications for them.
If
you, as a US person, receive a gift of more than $100,000 from a foreign
person, you are required to submit a Form 3520 to the IRS. Form 3520 is
an informational form only. You do not report a gift received on your
personal tax return, regardless of the amount received.
IRS
Form 3520 - http://www.irs.gov/pub/irs-pdf/f3520.pdf
IRS
Form 3520 instructions - http://www.irs.gov/pub/irs-pdf/i3520.pdf
http://www.irs.gov/Businesses/Gifts-from-Foreign-Person
