Punycode ?

Punycode is a simple and efficient transfer encoding syntax designed for use with Internationalized Domain Names in Applications (IDNA).  It uniquely and reversibly transforms a Unicode string into an ASCII  string.  ASCII characters in the Unicode string are represented  literally, and non-ASCII characters are represented by ASCII characters that are allowed in host name labels (letters, digits, and hyphens).

With this tool you can decode and encode the multilingual domains that use the ACE encoding.