[furryoldlobster]

So you're a magic user?  Awesome!  Let's spell this all out for ya...

First things first, on your character sheet, right under your 'HP' should be your SP or strain points.  At level 1, its the same as your intelligence.  The idea of strain is a little different than most D & D games.  It represents the effort it takes to complete a spell.  The higher the spell, the tougher it'd be to cast it. 

Check out this (probably poorly formatted for now) table:

Level                     Strain Cost
                0th    1st    2nd    3rd    4th    5th    6th    7th    8th    9th
1st            3       7     —     —     —     —     —     —    —     —
2nd           3       6     9      —     —     —     —     —    —     —
3rd            2       5     8     11     —     —     —     —    —    —
4th            1       4     7     10     13    —     —     —    —    —
5th            0       3     6      9      12     15     —     —    —    —


At level 1, you may cast level 0 and level 1 spells.  As you level up, these spells get easier, and easier,  to accomplish. 

Ok, so now we know the mentally draining effect of casting...but what exactly can we cast?

This version of D & D treats different schools of magic as unique skills.  Here's the spells for mage/sorcerer:
http://claytonia.net/forums/index.php?topic=2923.0
And here's the cleric's
http://claytonia.net/forums/index.php?topic=3195.0

Notice the words in bold?  Abjur (abjurations), conj (conjuration), div (divination), ench (enchantment), evoc(evocation), illus(illusion), necro(necromancy, trans(tranmutation), and univ(universal). As a wizard, you are limited to the spells you can learn by school.  You need to have studied enchantment to perform enchantment spells.  As you level up, you may choose additional schools, or improve a current one.  Spell are also limited by level.  In order to preform 2nd level conjuring spells, you need to have conj 2 as a unique skill.  The only exception to this are universal spells.  A wizard of any school may use these spells (still limited by character level.  A level 1 mage can't use 9th level universal spells until he's also level 9).