Human references can be divided into three classes: friend, wizard, sysadmin.

Your first point of contact should be a friend or collegue who knows a little more about UNIX than you do. It is quite possible that they won't be able to answer your question, but if they can, they will likely be able to explain it in a way that you can actually understand.

Your next point of contact is a UNIX wizard--someone who has many years experience working with UNIX. These are the people that lots of people go to so probably try to minimize the number of questions people ask. And the answer may not be comprehensible. The helpfulness of these people is usually inversely proportional to the number of times they have answered your particular question and is inversely proportional to the cube of the number of times you have asked your particular question.

There are some cases where you must contact your system administrator. If you forgot your password, you'll take some guff, but the sysadmin is the only one who can give you a new one. These people are normally much more concerned with LDAP, IMAP, and DNS than they are with explaining how to use a pipe.

A useful web site for UNIX help is maintained at the University of Edinburgh.

Some useful references published the old fashioned way include the "For Dummies" series by Levine and Young published by IDG books, a series of several somewhat advanced UNIX topics by OReilly and Associates, and the "nutshell" books also by OReilly and Associates.