The actual domain he’s selling is: xn--gamblng-cza.com
If you’re browser can handle IDNs you can type in gamblíng.com but otherwise you have to type xn--gamblng-cza.com
The jury is still out on whether IDNs have much value, my opinion is that they don’t.
Convertor is here http://www.sedo.co.uk/idn/index.php4