Becoming a mage is an involved process in this game.  It took me about 11 hours to do so according to the save game info.
 
During the process I wasn't really sure if I was on the right track.  Since it was obviously going to take some time to accomplish this goal I really didn't fancy coming to the realization some hours down the road that I'd made a wrong turn.
 
If you want to fast-track your way to magedom like I did, here is what you have to do (minimal spoilers):
 

1. Leave the beach and follow the path to Jan.  He can guide you to Harbor Town.
2. Jan will guide you to a small farm occupied by novices (people training to become mages).  Do their quests and then one of them can guide you to the northern entrance to Harbor Town.  If you enter Harbor Town through the main gate you will be recruited by the Order, be forced to become a Warrior of the Order and you will not be able to become a full mage.
3. Once inside Harbor Town find Master Belshwur.  Do his quests until he says he'll give you his recommendation.  At this point one of the Warriors of the Order on the street will tell you Commandant Carlos wants to see you.
4. Head up to the guard house and do the quests for Commandant Carlos.  Choose to side with the Order whenever the choice presents itself.  Once you've done his quests Carlos will give you his recommendation and allow you to leave the city.
5. Leave Harbor Town and head north to the Monastery at the foot of the volcano.  Once inside you'll be greeted by Master Pallas.  He will offer you a choice: become a Warrior of the Order or follow the path of magic and become a Mage.  Choose the path of magic obviously.
6. Complete your training and there you go.  Welcome to the Convocation of Mages!

1. Complete your basic training with Master Aric before doing anything else in the Monastery to avoid a possible bug.
2. Some of the training will require you to leave the Monastery.
3. Save your Learning Points and as much gold as you can for mage-related training from the Masters inside the Monastery.
   

Well, I do have a question.  I did all the masters quests to study crystal magic and I can't for the life of me finish the quest.  Am I missing something crucial?  I found Abrax, Cryus, Ignat, and Vitaus and Pallas doesn't offer me a quest.

Well, let's see.  Are you sure you completed everything? 
 
(from memory so I hope it's all here)
 

• Abrax: find his laboratory, locate his apprentices, gather the plants he wants
• Aric: complete basic training before doing the Hemlar murder quest
• Cyrus: visit Severin at Tilda's farm and gather the artifacts he wants
• Ignatius: read all the bookstands in the library including all those located in the hidden section you go through to reach Abrax, find the Fire Crystal
• Illumar: complete scroll making training
• Vitus: complete both the Trust and Wisdom portions of his quest, Trust is finding a replacement for the pig shit shoveling novice, Wisdom is giving the novice in the library the book he wants
• Pallus: has no quest but will recommend you after you've done the rest of the quests for the other Masters
  

I figured it out.  Thanks Bane.  I screwed up my game by saying I finished Pallus quest but what I really had to do was go back to town and ask if he had anything else for me to do.