After loading 3.1 You have to accept the User Agreements before you can
use the online channels such as Weather, WiiVote etc. Problem was when I loaded 3.1 it turned off WiiConnect24 and would not let me connect online to accept User agreements. I checked my wireless connection and it told me all was well. Catch 22!
I connect using a My Essentials router (Belkin). After calling Wii support and getting nowhere it was suggested that I log into the router and check the settings there, also no help. Finally they suggested disabling the security settings and firewall on the router and then try connecting the Wii. Success. Before turning back on the router security I made sure that WiiConnect24 was on and now all is back to normal.