The Win32.Klez virus is currently spreading fast as most virus programs that have not been updated since late last week will not detect it. In many cases once you are infected the virus will actually disable or corrupt your virus program. For those who have been infected, or are concerned they may have been, you can obtain a removal tool from Symantec at the following address which will not only detect but also remove the virus if found, even if you dont have a virus program:
Link to the tool on the Symantec website
Link to the tool on the Symantec website