A warmage is mostly artillery, like an archer who uses spells instead of arrows.
Try this:
Kobold warmage 6
Small-size Male Kobold
Warmage 6
Hit Dice: (6d6)+12
Hit Points: 38
Initiative: +3
Speed: Walk 30'
AC: 19
Face/Reach: 5 ft./5 ft.
Special Qualities: Light Sensitivity
Saves: Fortitude: +4, Reflex: +5, Will: +3
Abilities: Str 4 (-3), Dex 16 (+3), Con 14 (+2), Int 16 (+3), Wis 8 (-1), Cha 19 (+4)
Skills: Concentration +11; Knowledge (Arcana) +6; Sleight of Hand +5; Spellcraft +12; Tumble +4; Use Magic Device +8; Appraise +3; Balance +3; Craft (trapmaking) +5, Profession (miner) +1, Bluff +4; Diplomacy +4; Hide +7; Search +5
Feats: Empower Spell, Point Blank Shot, Precise Shot, Simple Weapon Proficiency
Alignment: True Neutral
Possessions: Amulet of Health +2; Headband of Intellect +2; Cloak of Charisma +2; Mithral chain shirt
Light Sensitivity (Ex): Kobolds are dazzled in bright sunlight or within the radius of a daylight spell.
Skills: Kobolds have a +2 racial bonus on Craft (trapmaking), Profession (miner), and Search checks.
With Point Blank Shot, Precise Shot, small size and decent dex, this guy will be really good at ray and orb spells. He'll also be decent at Use Magic Device, especially with scrolls, for some more flexible spellcasting options.
I may have given him too much equipment. Check the DMG table for wealth.
One trick I like to use with my gnome warmage: drop prone and fire your spells from a distance. Being prone gives no penalty on your spellcasting, but it gives a -4 on ranged attack rolls against you. If anybody looks like they'll get close, use a move action to stand up.