In case you haven't heard the news, and probably everyone has, ICANN has passed, by unanimous vote, to "relax" the rules that limit the top-level domains. "Relax" is maybe an understatement. The phrase might be "completely rewrite the internet".
To make a long story short, for the low, low price of $50,000 to $100,000, you too can create and own a top level domain (TLD). ANY unused TLD, up to 64 characters. As you might imagine, this will shake things up a little more than when they added .mobile and the other > 3 char names.
We don't have to worry about it until 2009, but it might not hurt to start taking a look at any DNS scripts that rely pre-conceived notions of how domain names should look.