If you look at the material tab with an object selected you will see that the material is presented in a list:



Clicking the + button adds another material to the object, clicking the - will delete one. You can add as many materials to the object as you require, and assign a texture to each material. Then you can select the vertices for a given material and click Assign to set them to that material.

If you look at the material tab with an object selected (Blender internal render, not Cycles) you will see that the material is presented in a list:



Clicking the + button adds another material to the object, clicking the - will delete one. You can add as many materials to the object as you require, and assign a texture to each material. Then you can select the vertices for a given material and click Assign to set them to that material.