I've included a summary of what constitutes a dual progression class edited into the 3rd or 5th post on the front page, and included an example character build that actually uses Rage Mage, to show how it can be used.
But no, Rage Mage isn't a dual progression class. But, make sure to check out those edits to ensure you use it properly (to ensure you won't lose caster levels, assuming you don't want to lose any).
Excellent. Then expect my build within the hour. (And don't worry, I definitely did not lose any caster levels.)
EDIT: Here's Agfinnr Varjersson, Barbarian//Sorcerer. I'll have fluff put together soon, but the gist of it is that he is a member of a Rashemi Berserker Lodge, but has left to find out who his father was. Even though he practices Seidr Magic, he has Runes tattooed on his body for the spells he knows to intimidate his opponents in battle.
[spoiler]
Agfinnr Varjersson(Human Barbarian 1//Sorcerer 1)Medium HumanoidHit Dice: 1d12+2 (14 HP)
Initiative: +1
Speed: 40 ft
Armor Class: 13 Touch: 11 Flat-footed: 12
Base Attack/Grapple: +1/+4
Attack: Greatclub+4(1d10+4)
Greatclub; enlarged+5(2d8+6)
Greatclub; raging+6(1d10+7)
Greatclub; raging, enlarged+7(2d8+9)
Spear+2(1d8+3)
Full Attack: Same
Space/Reach:5/5 (10/10 when enlarged)
Special Qualities: pounce, Weasel Familiar
Saves:+4/+3/+1
Abilities: Str 16, Dex 12, Con 14, Int 12, Wis 8, Cha 14
Skills: Concentration +6, Intimidate +6, Knowledge (Arcana) +5, Spellcraft +5, Jump +7
Feats: Power Attack, Versatile Spellcaster
Alignment: CG
Languages Spoken: Common (Rashemi), Draconic
Possessions:
Leather Armor
Greatclub
Spear
Backpack
Bedroll
Flint & Steel
1 day Trail Rations
Clay Mug
Knife
0gp 0sp 4cp
Daily Abilities:
rage (1/day)
Spells per day:
0: 5
1: 3+1
2: 0+1
3:
4:
5:
6:
7:
8:
9:
Spells known:
0: Resistance
Prestidigitation
Flare
Caltrops
1: Fist of Stone
Enlarge Person
2:
3:
4:
5:
6:
7:
8:
9:
Character background (rough):
Agfinnr grew up never knowing his father. He was taught Seidr Magic and the Draconic speech by his mother, and at a young age he discovered his ability to fly into a berserker Rage. When he came of age, he left his lodge to find his father and meet him.
Appearance: Agfinnr is tall and muscular, standing well over six feet tall and weighing 250 pounds. He has pale blond, nearly white hair, and he has tattooed himself with Runes that correspond to his magical abilities.
Familiar:
Hradi:Skills & Feats Balance +10, Climb +10, Hide +11, Move Silently, Spot +3, Weapon Finesse, Alertness
[/spoiler]