Today the .gov top level domain (U.S. government) was DNSSEC signed. As per "OMB Memo 08-23", all U.S. government agencies must DNSSEC sign their DNS zones (ending with .gov) before the end of 2009.
Federal agencies using Simple DNS Plus will be able to DNSSEC sign their zones in the upcoming Simple DNS Plus v. 5.2 (beta version available now). For details see: - How to DNSSEC sign a zone with Simple DNS Plus
Using the DNS Look Up tool in Simple DNS Plus 5.2, we can see that the ".gov" zone was indeed signed on February 5th 2009 at 12:01:02 PM (UTC):
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