A congressional act granting an executive "kill switch" for the internet was proposed in June 2010. It was called the Protecting Cyberspace as a National Asset Act, and it never came up for vote in Congress (i.e. died).
There is a revised version of the bill in Congress now (introduced in February 2011) called the Cybersecurity and Internet Freedom Act of 2011. According to the bill's sponsor, Joe Lieberman, the revised version contains no kill switch. However, it seems that this may not be true, according to this CNET article:
The new version follows the same process as the old one: President Obama would be given the power to "issue a declaration of a national cyberemergency." Once that happens, Homeland Security would receive sweeping new authorities, including the power to require that so-called critical companies "shall immediately comply with any emergency measure or action" decreed.
No "notice" needs to be given "before mandating any emergency measure or actions." That means a company could be added to the "critical" infrastructure list one moment, and ordered by Homeland Security to "immediately comply" with its directives the next.
It seems that if this is so, they could label all ISPs "critical" and prevent anyone from accessing the internet. It would probably be a lot more paperwork, but I don't think that would discourage them.
So yes, this new bill (which is still in the early stages of legislature, as far as I can tell), seems to contain a weakened form of the "kill switch", but not an executive one. It wouldn't be up to the President, or any other single person, but an entire governmental department.
You can read the entire bill here, but unless you can speak legalese, you might not be able to make sense of any of it, let alone know where to start. (It's unfortunate that I can't really answer your question directly from reading the bill, but such is American politics-- have to rely on sometimes-dubious third parties like news outlets to interpret legislature by proxy).