It didn't look like anyone had answered you question on PM'ing..
with most users... left click on their avatar and a menu will come up. Private message is usually an option, but if the person is pretty new it might not be.
visitor message like I have done is always available by going to that persons page. That option is in the menu as well. Just remember visitor messages are public.. so you don't want to put personal info in it that you don't want everyone able to see.
