MetadataItem

package mrkirby153.MscHouses.items;

import java.util.List;

import net.minecraft.client.renderer.texture.IconRegister;
import net.minecraft.creativetab.CreativeTabs;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.util.Icon;
import net.minecraft.util.MathHelper;
import cpw.mods.fml.relauncher.Side;
import cpw.mods.fml.relauncher.SideOnly;

public class FOO extends Item{
    public static final String[] itemNames = {"item1", "item2", "item3", "item4", "item5"};

    @SideOnly(Side.CLIENT)
    private Icon[] iconList;
    public FOO(int par1) {
        super(par1);
        this.setHasSubtypes(true);
        this.setMaxDamage(0);
        this.setCreativeTab(CreativeTabs.tabBlock);
    }

    @Override
    @SideOnly(Side.CLIENT)
    public Icon getIconFromDamage(int par1) {
        int i = MathHelper.clamp_int(par1, 0, 15);
        return this.iconList[i];
    }

    @Override
    @SideOnly(Side.CLIENT)
    public void registerIcons(IconRegister par1IconRegister) {
        this.iconList = new Icon[itemNames.length];

        for(int i = 0; i < itemNames.length; i++){
            this.iconList[i] = par1IconRegister.registerIcon("mschouses:testItem_" + itemNames[i]);
        }
    }

    @Override
    @SideOnly(Side.CLIENT)
    public void getSubItems(int itemID, CreativeTabs tab,
            List itemList) {
        for(int i = 0; i < itemNames.length; i++){
            itemList.add(new ItemStack(itemID,1,i));
        }
    }

    @Override
    public String getUnlocalizedName(ItemStack item) {
        return this.getUnlocalizedName() + "." + itemNames[item.getItemDamage()];
    }

}
------------------
To add localized names:

String[] itemNames = {"item", "Item 2", "Item 3", "Item 4", "Item 5" };
        for(int i = 0; i < itemNames.length; i++){
            LanguageRegistry.addName(new ItemStack(YOURITEMNAMEHERE,1,i), itemNames[i]);
        }