Your typically scaffold controller

users_controller.rb

class UsersController < ApplicationController

  respond_to :html, :xml

  def index
    @users = User.all
    respond_with(@user)
  end

  def show
    @user = User.find(params[:id])
    respond_with(@user)
  end

  def new
    @user = User.new
    respond_with(@user)
  end

  def edit
    @user = User.find(params[:id])
  end

  def create
    @user = User.new(params[:user])
    if @user.save
      respond_with(@user) do |format|
        format.html { redirect_to(@user, :notice => 'User was successfully created.') }
        format.xml  { render :xml => @user, :status => :created, :location => @user }
      end      
    else
      respond_with(@user) do |format|
        format.html { render :action => "new" }
        format.xml  { render :xml => @user.errors, :status => :unprocessable_entity }
      end
    end
  end

  def update
    @user = User.find(params[:id])

    if @user.update_attributes(params[:user])
      respond_with(@user) do |format|
        format.html { redirect_to(@user, :notice => 'User was successfully updated.') }
        format.xml  { head :ok }
      end
    else
      respond_with(@user) do |format|
        format.html { render :action => "edit" }
        format.xml  { render :xml => @user.errors, :status => :unprocessable_entity }
      end
    end
  end

  def destroy
    @user = User.find(params[:id])
    @user.destroy

    respond_with(@user) do |format|
      format.html { redirect_to(users_url) }
      format.xml  { head :ok }
    end
  end
end