using (SPWeb web = site.OpenWeb()) //Can user SPContext.Current.Web
                {
                    SPNavigationNodeCollection quickLaunchNodes = web.Navigation.QuickLaunch;

                    //Parent
                    foreach (SPNavigationNode node in quickLaunchNodes)
                    {
                        string strParentTitle = node.Title;
                        string strParentURL = node.Url.ToString();
                        Console.WriteLine("Parent : " + strParentTitle + " : " + strParentURL);
                        //Children
                        SPNavigationNodeCollection children = node.Children;
                        foreach (SPNavigationNode child in children)
                        {
                            string strTitle = child.Title;
                            string strURL = child.Url.ToString();
                            Console.WriteLine("Child : " + strTitle + " : " + strURL);
                        }
                    }

                }