Index: app/helpers/users_helper.rb
===================================================================
--- app/helpers/users_helper.rb	(revision 3892)
+++ app/helpers/users_helper.rb	(working copy)
@@ -54,4 +54,38 @@
     end
     tabs
   end
+
+  def users_to_csv(users)
+    ic = Iconv.new(l(:general_csv_encoding), 'UTF-8')    
+    decimal_separator = l(:general_csv_decimal_separator)
+    export = FCSV.generate(:col_sep => l(:general_csv_separator)) do |csv|
+      # csv header fields
+      headers = [ l(:field_login), 
+                  l(:field_firstname),
+                  l(:field_lastname),
+                  l(:field_mail),
+                  l(:field_admin),
+                  l(:field_created_on),
+                  l(:field_last_login_on)
+                  ]
+      # Export user custom fields
+      custom_fields = UserCustomField.all
+      custom_fields.each {|f| headers << f.name}
+      csv << headers.collect {|c| begin; ic.iconv(c.to_s); rescue; c.to_s; end }
+      # csv lines
+      users.each do |user|
+        fields = [user.login,
+                  user.firstname, 
+                  user.lastname,
+                  user.mail, 
+                  user.admin,
+                  user.created_on,
+                  user.last_login_on
+                  ]
+        custom_fields.each {|f| fields << show_value(user.custom_value_for(f)) }
+        csv << fields.collect {|c| begin; ic.iconv(c.to_s); rescue; c.to_s; end }
+      end
+    end
+    export
+  end
 end
Index: app/controllers/users_controller.rb
===================================================================
--- app/controllers/users_controller.rb	(revision 3892)
+++ app/controllers/users_controller.rb	(working copy)
@@ -24,6 +24,7 @@
   include SortHelper
   helper :custom_fields
   include CustomFieldsHelper   
+  include UsersHelper
 
   def index
     sort_init 'login', 'asc'
@@ -41,12 +42,16 @@
     @user_pages = Paginator.new self, @user_count,
 								per_page_option,
 								params['page']								
+    limit = (params[:format] == 'csv') ? nil : @user_pages.items_per_page
     @users =  User.find :all,:order => sort_clause,
                         :conditions => c.conditions,
-						:limit  =>  @user_pages.items_per_page,
+						:limit  =>  limit,
 						:offset =>  @user_pages.current.offset
 
-    render :layout => !request.xhr?	
+    respond_to do |format|
+      format.html { render :layout => !request.xhr? }
+      format.csv  { send_data(users_to_csv(@users), :type => 'text/csv; header=present', :filename => 'export.csv') }
+    end
   end
   
   def show
Index: app/views/users/index.rhtml
===================================================================
--- app/views/users/index.rhtml	(revision 3892)
+++ app/views/users/index.rhtml	(working copy)
@@ -45,4 +45,8 @@
 </div>
 <p class="pagination"><%= pagination_links_full @user_pages, @user_count %></p>
 
+<% other_formats_links do |f| %>
+	<%= f.link_to 'CSV' %>
+<% end %>
+
 <% html_title(l(:label_user_plural)) -%>