If you are referring to Warband, there are no halberds in the native game files. There are plenty of nice models to use that people have made for mods, though, and they aren't hard to add with Morgh's Editor. I tried one out for my own mod (gave it a medium length for polearms, strong thrust, and decent swing) and it sure was effective against calvary and even some infantry units. It's the only way you can get halberds in Warband, but it really isn't hard to do with Morgh's Editor; techniquely you would still be playing the native game with just halberds added to it (and you can use Morgh's to give the halberds to the Rhodok troops). If you are interested in doing so, I can link you to a decent brf with some halberds to choose from and walk you through adding them with Morgh's.
