If you are using the newer 'nyu' wireless network for accessing NYURoam, you will be -- or, perhaps, very recently were -- presented with a dialog box asking you to validate a new server certificate. Simply accept the new certificate and log on as usual. No further action is necessary, and you will not need to validate the certificate again until 2009.
Windows compatibility issues resolved! Difficulties experienced Wednesday, Jan. 23 by people trying to connect via "nyu" from Windows computers have been resolved. If you were trying to access NYURoam via "nyu" over the past few days and were experiencing difficulties, you can now resume using "nyu". (No difficulties were encountered with connections from Macintosh computers.)
For more about 'nyu' and NYURoam, see http://www.nyu.edu/its/wireless/configure/.