Welcome aboard! JugglingReferee is another canadian official who posts often on this site. You are correct about K and R being the kicking and return teams. Things are a bit slow right now, but will pick up throughout the summer.
A couple of other links to officials discussion boards you may want to look at are,
http://www.nfhs.org/cgi-bin/ultimate...?ubb=forum;f=9 which is for national federation ball only, and
http://www.refstripes.com/forum/index.php#1 which has NF and NCAA discussions.