Zaalbar's stats are the stuff of dreams for munchkin players everywhere; even Bill Gates would think twice before raising his attributes to levels like those of Zaalbar. Obviously enough, the melee bonuses from his 20 strength and the extra Vitality from his 20 constitution make Zaalbar a great candidate to wield a sword during combat; you just have to keep an eye on his health, since he can't wear armor and has almost no dexterity bonus to his defense. This defensive problem will curtail Zaalbar's usefulness in the late game, where enemies have high attack bonuses and deal more damage. Your other characters will have defense ratings in the high 20s near the end of the game, while Zaalbar will remain closer to 12 or 13, meaning that he'll take an awful lot of damage very quickly. In the early parts of the game, however, Zaalbar is going to be one of your party's prime killers.
Attributes: If you actually want to use Zaalbar for any significant portion of the game, he'll need more dexterity than he starts out with, in order to raise his defense. This is also what you should use his implant slot for, providing you find decent dexterity implants.
Skills: Computer use and repair are Zaalbar's raison d'etre, but you know our opinions on those skills. Still, they might come in handy during the sections of the game where Zaalbar is still running around with your party, so you might as well indulge yourself.
Feats: Melee feats are where it's at; mastering both flurry and dueling will help Zaalbar deal immense amounts of damage, plus give him a bit of a bonus to his defense.