Admissions are charged even for affiliated folks, actually, unless you have a membership, which is 15 bucks, I believe, and limited to students and alumni. Guests are never a problem, however, though they pay the same amount.
It is a good beer bar--I have quaffed many a pint there over a book and some guac, or with friends. It's rather more expensive than Jimmy's, but utterly worth it, especially compared to other establishments across the city. Between those two, most any Hyde Parker should be pleased--I know I am.