Internationalized domain names (IDN) are now supported in WhoisThisDomain and DNSDataView utilities
The new versions of WhoisThisDomain and DNSDataView utilities allow you to type domain names which contain non-English characters (internationalized domain names).
when you type a domain with non-English characters, it automatically converted to its Ascii form (Which looks like xn--aaaaaa.com) before sending it to the Whois/DNS server.
However, be aware that I currently use the internal IDN support provided by Windows operating system, which was added starting from Windows XP with service pack 2,
so this new feature may not work on systems prior to XP/SP2.
You can check whether your Windows OS supports IDN by searching for normaliz.dll inside your system32 directory.
If this file exists, it means that your system has IDN support.