(See also "What is HarvardKey and do I need to register?")
Once you claim your HarvardKey, Harvard WiFi no longer works with HUID and PIN-password; you will get an invalid credentials message. Instead, for username continue to use HUID, but for the password use the new password you just created for HarvardKey. For the WiFi network "Harvard Secure" this is noted here: http://reference.iam.harvard.edu/harvardkey#step3.
For the unsecure WiFi network "Harvard University" you will need to re-register your device; go to https://registration.noc.harvard.edu and proceed as you would for your annual re-registration or registering a new device. Again, the username will be your HUID and the password will be your new HarvardKey password.
You do not need to claim your HarvardKey in order to use Harvard WiFi, as the HUID/PIN mechanism will continue to work until further notice. However, some of you may wish to claim your HarvardKey now for other reasons, and you can do so and continue to access Harvard WiFi as described above. Please contact firstname.lastname@example.org if you need further assistance with Harvard WiFi.