-Spellbook: similiar to 3.5, wizards have a spellbook. However, this spellbook functions more like sorcerer spells known than an actual book- wizards can no longer copy spells into it. The only way a wizard can learn new spells is as part of leveling up (a wizard still learns 2+int mod at first level, and 2 spells per level at every subsequent level).
Spell Levels: Wizards now use the spell progression of a sorcerer (e.g. they gain acess to 2nd level spells at 4th level, 3rd level spells at 6th level, ect). The exception to this is a wizard's specialized school, in which he gains access to spells 1 level earlier. Additionally, spells now have pre-requisites- in order to learn a higher level spell in a school, a wizard must know a certain number of lower level spells from that school (similiar to martial disciplines from Tome of Battle).
Limitations on 7th, 8th, and 9th level daily spells- all prepared casters are limited to having a certain number of high level spells prepared. See general spellcasting.
Spellcasting: Wizards use the new spellcasting system- see General Casting for further details.
Spell List: The wizard/sorcerer spell list has been drasticly reworked in order to balance the different schools. Many new spells have been added, and several spells have had their level increased. The overall list is much smaller than it was in 3.5, however wizards now have the option of modifying or inventing new spells of their specialized school.
-the meta-magic system has been replaced by the ability to research new spells- one way this can be done is applying meta-magic like effects to existing spells. This does not require a feat to do, however it does use up one of the wizard's spells gained when he levels up- as the process creates a new and distinct spell.
-the system is designed for specialization. Specialist wizards choose one school to focus in at first level, and four prohibited schools (of which divination may be one). They do not gain extra spells per day in their school- however they gain access to spells of their specialized school one level earlier, and the ability to modify existing spells or research new ones in their specialized school. Wizards gain a second specialized school at level 10.
Generalist wizards- don't get to take advantage of much of the advantages of this system, however they do gain one extra spell per encounter, and one extra spell per day.
-Bonus metamagic/item creation feats
A wizard no longer gains bonus feats every 5 levels, he does however still gain scribe scroll at 1st.
A wizard no longer gains a familiar. A wizard may give up Scribe Scroll in order to obtain a familiar, or may take the feat Obtain Familiar (CArc). (If a player just wants a animal to follow them around for flavor purposes, feel free to grant them this, however it does not gain any of the normal benefits of a familiar).
In addition to spell effects scaling better with level, the base save DCs for spells are now 10 + 1/2 Caster Level + Primary Ability Modifier.
-Metamagic: metamagic as it existed in 3.5 no longer exists. Arcane casters however, are inherently capable of creating new spells by applying metamagic like effects to base spells they already know. For example, when a specialist wizard levels up he gets to add new spells to his spellbook- he could add new spells off the core list, or he could invent a new spell by adding an effect to a lower level spell he already knows, effectively upgrading the spells to a newer version. This option is available to arcane casters only- divine casters no longer have access to any sort of metamagic-like effect.
-Spell Prerequisites: The schools of spells are now organized more like the martial disciplines. Efforts have been made to balance them, and prerequisites have been added, based on spell levels. These only apply to arcane casters- divine spells do not have prerequisites. Wizards must have the indicated number of spells of the same school in their spellbook before they can learn new spells of that school. Sorcerers must know half this number rounded down. Note that the way arcane casters learn spells has changed as well (wizards get 3/level and can no longer copy from other sources, and sorcerers get 1 at every level.
2nd: 1 of the same school
3rd: 2 of the same school
4th: 3 of the same school
5th: 4 of the same school
6th: 5 of the same school
7th: 7 of the same school
8th: 9 of the same school
9th: 11 of the same school