For GH Warriors of Rock, there is no real friendcode, for so far I know... What you can do is (if you configured the WiFi settings of your Wii) search players, and play a few songs. Whenever you played a song online, you can go to the playerslist and send an invitation. If the other player accepts, you have a friend in your ''Musicians list''. Hope this helped!
man, u have facebook? kk if you have pass me or add me www.facebook.com/vertuanbellati
if you have time a realy want to play tonight kkk on gh: metallica
It sure is possible to play online. Nintendo announced that they will remove the online WiFi possibility for Wii and DS about a month ago, but Nintendo still hasn't done it. For as long as they don't do anything, it is still possible. Nintendo said that online gameplay will be removed, though the possibility to buy DLC and other games/demo's will not be removed.