If it comes back red, there are steps you can take. The FBI as well as the DNS Changer Working Group (DCWG) have sites set up to guide you through the process that you can get to at the bottom of this post. The most important thing to remember is that if your check does come back red, as I mentioned that means that you could be vulnerable to additional malware and viruses.
Check in with your local nerd if you have any issues or questions. I've also set up a temporary email address you can send your questions to through July 9th, at email@example.com.
DNS Changer Checker: http://dns-ok.us
Official FBI DNS Changeer website: http://www.fbi.gov/news/stories/2011/november/malware_110911
DCWG DNS Changer website: http://www.dcwg.org/